PodcastPUP
The Search Portal For PodCast

PodcastPUP Forum
Try The New PUP Search "Powered By Google"

  Submit PodCast Site       Recently Submitted PodCast Sites PodcastPUP  

Foundations of Amateur Radio  RSS Feed  Subscribe Via iTunes  Zune Subscribe
0 star rating Average rating based on 0 votes  -  Rate
Link To This Page: http://www.podcastpup.com/pod.asp?ID=14605
Voting Link: http://www.podcastpup.com/pod_vote.asp?ID=14605
Category: Games/Hobbies
Receive Email When This Podcast Updates
Email:
PupuPlayer FREE
Click Button To Listen To All Episode's
Question Regarding This Entry?


My Yahoo!  Google Reader  My MSN  podnova  NewsGator  Odeo


Description:

The wonderful hobby of HAM Radio can be daunting and challenging but can be very rewarding. Every week I look at a different aspect of the hobby, how you might fit in and get the very best from the 1000 hobbies that Amateur Radio represents.

Sponsored Links




Amazon.com

Aloha Podcast Network

Hawaii Podcast
Podcast Episode's:
All the power in the observable universe expressed in milliwatts ...
Foundations of Amateur Radio <p> If you've been following my amateur radio journey, you'll have likely noticed that I've been straying from the fold. The words I use for power have been changing. I've reduced references to Watt and increased use of the term decibel. <p> Initially this was incidental, recently it's been more of a deliberate decision and I'd like to explain how this came to be. It starts with representing really big and really small numbers. <p> Let's start big. <p> On 14 September, 2015 the first direct observation of gravitational waves was made when a pair of black holes with a combined estimated weight of 65 solar masses merged. The signal was named GW150914, combining "Gravitational Wave" and the observation date to immortalise the event. <p> Following the collision, it was estimated that the radiated energy from the resulting gravitational waves was 50 times the combined power output of all the light from all the stars in the observable universe. As a number in Watts, that's 36 followed by 48 zeros. If you're curious, there's even a word for that, 36 Quindecillion Watts. <p> Now let's look at small. The typical signal strength received from a GPS satellite, like say by your phone, is about 178 attowatts, or in Watts, 0.000 and so on, in all, 13 zeros between the decimal point and then 178. <p> What if I told you that the energy associated with the collision of those two black holes could be expressed in comparison with a milliwatt. Remember, this collision emitted more energy than all the output of light from all the stars in the observable universe. The expression for all that power is 526 dBm. <p> Similarly, the tiny received GPS signal can be expressed as -127.5 dBm. <p> Just let that sink in. All the power in the observable universe through to the minuscule power received by the GPS in your phone, all expressed between 526 dBm and -127.5 dBm, and not a zero in sight. <p> As I mentioned, the unit dBm relates to a milliwatt. As a starting point, let me tell you that 1 Watt is 1,000 milliwatts and is represented by 30 dBm. <p> The decibel scale doesn't work quite the same as other number ranges you might be used to. Adding the value 3 doubles its size and adding the value 10 increases its size by a factor 10. <p> For example, to double power from 1 Watt or 30 dBm, add 3 and get 33 dBm, which is the same as 2 Watts. If you want to increase 1 Watt by a factor 10, again, starting with 30 dBm, add 10 and get 40 dBm which is 10 Watts. Similarly, 50 dBm is 100 Watts and 60 dBm is 1,000 Watts. <p> Going the other way, halving power, remove 3. So taking 3 from 60 dBm is 500 Watts or 57 dBm. Dividing power by a factor 10 works the same, take 10. So 47 dBm is 50 Watts and 37 dBm is 5 Watts. <p> If you get lost, remember, dBm relates to a milliwatt. 1 Watt is 1,000 milliwatts and is represented by 30 dBm. Divide by a factor 1,000, remove 30 and end up with 0 dBm, which is the same as 1 milliwatt. I'll say that again, 0 dBm is the same as 1 milliwatt. <p> It takes a little getting used to, but you can do some nifty things. For example, remove 10 to get a tenth of a milliwatt, or -10 dBm. <p> This same process of adding and subtracting applies in other ways too. Attenuation, or making a signal weaker, and amplification, or making a signal stronger can use the same rules. <p> For example, if you apply 3 dB of attenuation, you're making the signal 3 dB weaker, or halving it, so you subtract 3 dB from your power output. If your amplifier is rated at 6 dB gain, you're quadrupling the output and you add 6 dB to your power output. <p> Similarly, if you talk about the gain of an antenna, you add it. If the gain is 20 dBi, you add it to the power output. You can use this for coax loss calculations as well. A 100m length of RG-58 at 28 MHz has a loss of 8 dB. You can directly subtract this from the power output of the transmitter and know precisely how much power is making it to the antenna. <p> There's more. The radio amateur S9 signal strength on HF, something which we consider to be a strong signal, can be expressed as -73 dBm or a very small fraction of a milliwatt. An S8 signal is 6 dB weaker, or -79 dBm. A 20 over 9 report is -53 dBm. I will point out that this is at 50 Ohm. <p> As a result, we now have a continuous scale for all the elements in the transmission chain between the transmitter and the receiver. <p> While I'm here, I've already mentioned that negative dBm readings relate to fractions of a milliwatt, so values between 0 and 1. <p> This highlights one limitation of this scale. We cannot represent 0 Watts. Mind you, that doesn't happen all that often. The thermal noise floor in space at 1 Hz bandwidth, that's at 4 kelvins, is -192.5 dBm, which practically means the minimum level of power we need to express. It's also a good value to remember because if you're doing funky calculations and you end up with a number less than -192.5 dBm, you can pretty much guarantee that you've probably made a boo-boo. <p> 0 Watts using the dBm scale is represented by negative infinity, or essentially a division by zero error, really not defined, so there's that. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Between decibels and milliwatts ...
Foundations of Amateur Radio <p> Between decibels and milliwatts ... <p> As you might recall, I've been working towards using a cheap $20 RTL-SDR dongle to measure the second and third harmonic of a handheld radio in an attempt to discover how realistic that is as a solution when compared to using professional equipment like a Hewlett Packard 8920A RF Communications Test Set. <p> I spent quite some time discussing how to protect the receiver against the transmitter output and described a methodology to calculate just how much attenuation might be needed and what level of power handling. With that information in-hand, for reference, I used two 30 dB attenuators, one capable of handling 10 Watts and one capable of handling 2 Watts. In case you're wondering, it's not the dummy load with variable attenuation that I was discussing recently. <p> I ended up using a simple command-line tool, rtl-power, something which I've discussed before. You can use it to measure power output between a set of frequencies. In my case I measured for 5 seconds each, at the base frequency on the 2m band, on the second and on the third harmonic and to be precise, I measured 100 kHz around the frequencies we're looking at. <p> This generated a chunk of data, specifically I created just over a thousand power readings every second for 15 seconds. I then put those numbers into a spreadsheet, averaged these and then charted the result. The outcome was a chart with three lines, one for each test frequency range. As you'd expect, the line for the 2m frequency range showed a lovely peak at the centre frequency, similarly, there was a peak for the other two related frequencies. <p> The measurement data showed that the power measurement for 146.5 MHz was nearly 7 dB, for 293 MHz it was -44 dB and for 439.5 MHz it was -31 dB. If you've been paying attention, you'll notice that I used dB, not dBm or dBW in those numbers, more on that shortly. <p> From a measurement perspective we learnt that the second harmonic is 51 dB below the primary power output and the third harmonic was about 38 dB below the primary power output. <p> First observation to make is that these numbers are less than shown on the HP Test Set where those numbers were 60 dB and 62 dB respectively. <p> Second observation, potentially more significant, is that pesky dB thing I skipped over earlier. <p> If you recall, when someone says dB, they're referring to a ratio of something. When they refer to dBm, they're referring to a ratio in relation to 1 milliwatt. This means that when I say that the power reading was 7 dB, I'm saying that it's a ratio in relation to something, but I haven't specified the relationship. As I said, that's on purpose. <p> Let me explain. <p> When you use an RTL-SDR dongle to read power levels, you're essentially reading numbers from a chip that is converting voltages to numbers. In this case the chip is an Analog to Digital Converter or an ADC. At no point has any one defined what the number 128 means. It could mean 1 Volt, or it could mean 1 mV, or 14.532 mV, or something completely different. In other words, we don't actually know the absolute value that we're measuring. We can only compare values. <p> In this case we can say that when we're measuring on the 2m band we get a range of numbers that represent the voltage measured along those frequencies. When we then measure around the second harmonic, we're doing the same thing, possibly even using the same scale, so we know that if we get 128 back both times we might assume the voltage is the same in both cases, we just don't actually know how much the voltage is. We could say that there's no difference between the two, or 0 dB, but we cannot say how high or low the voltage is. <p> This is another way of describing something I've discussed before, calibration. <p> So, if I had a tool that could output a specific, known RF power level, and fed that into the receiver and measured, I could determine the relationship between my particular receiver and that particular power level. I could then measure at all three frequencies and determine if the numbers were actually the same for these three frequencies, which is what I've been assuming, but we don't actually know for sure right now. <p> So, at this point we need a known RF signal generator. The list of tools is growing. I've already used a NanoVNA to calibrate my attenuators and I've used a HP RF Communications Test Set to compare notes with. <p> At this point you might realise that we're not yet able to make any specific observations about using a dongle to make harmonic measurements, but you can make pretty pictures... <p> There's a good chance that you're becoming frustrated with this process, but I'd like to point out that at the beginning of this journey I can tell you that I had no idea what the outcome might be and obviously, that's the nature of experimentation. <p> If you have some ideas on how to explore further, feel free to get in touch. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Wet and Blue adventures with coax ...
Foundations of Amateur Radio <p> Over the weekend a friend of mine convinced me to help plant some trees. Mind you, I was told that this was going to be a blue tree painting day. The Blue Tree Project is now a global awareness campaign that paints dead trees blue to spread the message that "it's OK to not be OK", and help break down the stigma that's still largely attached to mental health. <p> In the process, I learnt that my physical stamina is not what it once was and my current appetite for bending over and shovelling dirt is, let's call it, muted. <p> After the digging and the sausage sizzle under the branches of an actual blue tree, there was some opportunity for playing radio, something I haven't done in much too long. I wasn't sure when I last got into the fresh air to actually listen, but I must confess, the coax cable that I picked up out of my shed had been hanging there for several years. <p> The location where we planned to play was in a rural setting, right next to a dam, which surprisingly actually had water in it. The idea was to set-up a vertical antenna with a couple of ground radials, plug in a radio and have a listen. I have to say, after the digging I was really looking forward to this. <p> My piece of coax, about 20 meters long, was used to connect the antenna to the radio so we could sit in the shade whilst the antenna stood out in the sun near the dam. <p> The antenna, a telescopic one, came with a ground spike and about eight radials and needed to be tuned to some extent, as-in, near-enough is close enough, since we had an antenna tuner with our radio. To achieve the tuning we wanted to connect a NanoVNA to the coax which was the first challenge. The BNC connectors on my coax were pretty dull, likely a combination of poor quality, accumulated dust, humidity and lack of use. <p> As an added bonus the centre pin on one end seemed a little bent. <p> After working out how to get an SMA adaptor into the connectors we were in business. Connected up between the antenna and the NanoVNA we set out to get things lined up. The SWR on the display, hard to read in the full sun at the best of times, seemed to be a little odd. Not something I could put my finger on, but if you've seen enough SWR plots you know what it's supposed to look like and for some reason it didn't. <p> We bravely carried on, connected the radio to the coax and started tuning around. Didn't seem to be a lot of activity on the 20m band. We couldn't hear the local NCDXF beacon which was odd. Also no FT8 activity, also odd. <p> If anything, it seemed like there was nothing happening at all. <p> Before we continue, I'll point out that this can happen with a big enough burp from the Sun. I hadn't seen any alerts, so I wasn't buying it. We removed my coax, plugged in something much shorter and the bands came alive with all the activity we'd been expecting. <p> And then it started to rain. <p> Seriously. Finally got out into the world, got radio activity going, had actual signals to tune to and it starts raining. Glynn VK6PAW and I took one look at each other, shook our heads and dashed for the radio to bring it under shelter. I put on my raincoat, and together we disassembled the antenna and the station and went home. <p> Clearly, my coax was faulty. Lesson learnt. Test your coax before you go out and you'll have a better outcome. <p> About that. <p> Today, a week later, I'm sitting on the floor of my shack with the offending coax between my legs, surrounded by adaptors, a NanoVNA, a RigExpert, a dummy load, a short and an open terminator. No matter how I test, no matter what I test, everything is as it should be. I can tell you that the Time Domain Reflectometry shows me that the coax is 25.8m long, useful information, but not really any surprise. <p> There's also no significant return loss, unless you head for 1 GHz, but even then it's perfectly respectable, if anything, better than I expected. <p> There are no loose connections, nothing rattling, nothing amiss. <p> The only thing that I can even begin to think might be the case is that one of the centre pins on one end of the coax is slightly shorter. Combined with "close enough is good enough" when I attached the SMA adaptor in the field, might account for a connection that never got made, since the adaptor wasn't seated deep enough. <p> So, I'm not quite ready to cut off the connectors and re-terminate this coax. I'll be taking it into the field again, but I'll make sure that I bring an alternative, just in case. I'm also leaving the SMA adaptors connected to the coax. Future me will thank me. <p> Oh, yes, in-case you're wondering, I'm slowly working out how to improve my stamina. That was not fun. If you want to know more about Blue Trees and its message, check out the BlueTreeProject.com.au website and if you ever just want to talk, get in touch. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Checking attenuation numbers ...
Foundations of Amateur Radio <p> Before we start I should give you fair warning. There are many moving parts in what I'm about to discuss and there's lots of numbers coming. Don't stress too much about the exact numbers. In essence, what I'm attempting is to explore how we can reduce the power output from a transmitter in such a way that it doesn't blow up a receiver whilst making sure that the signal is strong enough that we can actually measure it. <p> With that in mind, recently I discussed the idea of adding a series of attenuators to a transmitter to reduce the power output by a known amount so you could connect it to a receiver and use that to measure output power at various frequencies. One hurdle to overcome is the need to handle enough power in order to stop magic smoke from escaping. <p> None of my attenuators are capable of handling more than 1 or 2 Watts of power, so I cannot use any of them as the first in line. As it happens, a good friend of mine, Glynn VK6PAW, dropped off a device that allows you to divert most of the power into a dummy load and a small amount into an external connector. In effect creating an inline attenuator capable of handling 50 Watts. <p> The label doesn't specify what the attenuation is, so I measured it using a NanoVNA. To make our job a little interesting, it isn't constant. Between 10 kHz and 1 GHz, the attenuation decreases from 70 dB to 10 dB. We want to measure at a base frequency on the 2m band and its second and third harmonic. The attenuation at those frequencies varies by 11 dB, which means we'll need to take that into account. <p> So, let's subject our currently imaginary test set-up to some sanity checking. Our receiver is capable of reading sensible numbers between a signal strength of -127 dBm and -67 dBm and we'll need to adjust accordingly. <p> If we transmit an actual 20 Watt carrier, that's 43 dBm. With 110 dB of attenuation, we end up at -67 dBm, which is right at the top end of what we think the receiver will handle. If we're using something like 5 Watts, or 37 dBm, we end up at -73 dBm, which is well above the minimum detectable signal. Our best harmonic measurement was around -30 dBm, which means that with 110 dB of attenuation, we end up at -140 dBm, which is 13 dB below what we think we can detect. <p> So, at this point you might wonder if this is still worth our while, given that we're playing at the edges and to that I say: "Remind me again why you're here?" <p> First we need to attenuate our 20 Watts down to something useful so we don't blow stuff up. Starting with 110 dB attenuation, we can measure our base carrier frequency and its harmonics and learn just how much actual power is coming out of the transmitter. Once we know that, we can adjust our attenuation to ensure that we end up at the maximum level for the receiver and see what we are left with. <p> So, let's look at some actual numbers, mind you, we're just looking at calculated numbers, these aren't coming from an actual dongle, yet. Using Glynn's dummy load as the front-end, at 146.5 MHz, the attenuation is about 30 dB. If we look at a previously measured handheld and rounding the numbers, it produced 37 dBm. That's the maximum power coming into our set-up. With 30 dB of attenuation from Glynn's dummy load, that comes down to 7 dBm. We'll need an additional 74 dB of attenuation to bring that down to -67 dBm, in all we'll need 104 dB of attenuation. <p> The third harmonic for that radio was measured at -26 dBm. So, with a 104 dB of attenuation that comes out at -130 dBm, which is below the minimum detectable signal supported by our receiver. However, remember that I told you that our dummy load had different attenuation for different frequencies? In our case, the attenuation at 439.5 MHz is only 19 dB, not 30, so in actual fact, we'd expect to see a reading of -119 dBm, which is above the minimum detectable signal level. <p> I realise that's a lot of numbers to digest, and they're specific to this particular radio and dummy load, but they tell us that this is possible and that we're potentially going to be able to measure something meaningful using our receiver. I'll also point out that if you're going to do this, it would be a good idea to take notes and prepare what numbers you might expect to see because letting the magic smoke escape might not be one of your desired outcomes. <p> Speaking of smoke, what happens if you consider changing the attenuation when you're measuring at another frequency, like say the second or third harmonic and you see a reading close to, or perhaps even below the detectable signal level as we've just discussed. You might be tempted to reduce the attenuation to increase the reading, but you need to remember that the transmitter is still actually transmitting at full power into your set-up, even if you're measuring elsewhere. This is why for some radios you'll see a measurement that states that the harmonics are below a certain value because the equipment used doesn't have enough range to provide an actual number. <p> To simplify my life, using a NanoVNA, I created a spreadsheet with 101 data points for the attenuation levels of Glynn's dummy load between 10 kHz and 1 GHz. I charted it and with the help of the in-built trend-line function determined a formula that matched the data. <p> I've also skipped over one aspect that needs mentioning and that's determining if the receiver you're using to do this is actually responding in the same way for every frequency. One way you might determine if that's the case is to look at what happens to the signal strength across multiple frequencies using a dummy load as the antenna. One tool, rtl_power might help in that regard. <p> Is this going to give you the same quality readings as a professional piece of equipment? Well, do the test and tell me what you learn. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How much attenuation is enough?
Foundations of Amateur Radio <p> Recently I had the opportunity to use a piece of professional equipment to measure the so-called unwanted or spurious emissions that a transceiver might produce. In describing this I finished off with the idea that you could use a $20 RTL-SDR dongle to do these measurements in your own shack. I did point out that you should use enough attenuation to prevent the white smoke from escaping from your dongle, but it left a question, how much attenuation is enough? <p> An RTL-SDR dongle is a USB powered device originally designed to act as a Digital TV and FM radio receiver. It's normally fitted with an antenna plugged into a socket on the side. I'll refer to it more generically as a receiver because much of what we're about to explore is applicable for other devices too. <p> Using your transceiver, or transmitter, as a signal source isn't the same as tuning to a broadcast station, unless you move it some distance away, as-in meters or even kilometres away, depending on how much power you're using at the time. Ideally we want to connect the transmitter output directly to the receiver input so, at least theoretically, the RF coming from the transmitter stays within the measuring set-up between the two devices. <p> Assuming you have a way to physically connect your transmitter to your receiver we need to work out what power levels are supported by your receiver. <p> For an RTL-SDR dongle, this is tricky to discover. I came across several documents that stated that the maximum power level was 10 dBm or 0.01 Watt, but that seemed a little high, since an S9 signal is -73 dBm, so I kept digging and discovered a thoughtful report published in August 2013 by Walter, HB9AJG. It's called "Some Measurements on DVB-T Dongles with E4000 and R820T Tuners". <p> There's plenty to learn from that report, but for our purposes today, we're interested in essentially two things, the weakest and strongest signals that the receiver can accommodate. We're obviously interested in the maximum signal, because out of the box our transmitter is likely to be much too strong for the receiver. We're going to need to reduce the power by a known amount using one or more connected RF attenuators. <p> At the other end of the scale, the minimum signal is important because if we add too much attenuation, we might end up below the minimum detectable signal level of the receiver. <p> Over the entire frequency range of the receivers tested in the report the minimum varies by about 14 dB, so let's pick the highest minimum from the report to get started. That's -127 dBm. What that means is that any signal that's stronger than -127 dBm is probably going to be detectable by the receiver and for some receivers on some frequencies, you might be able to go as low as -141 dBm. <p> At the other end of the scale the report shows that the receiver range is about 60 dB, which means that the strongest signal that we can use is -67 dBm before various types of distortion start occurring. For comparison, that's four times the strength of an S9 signal. <p> So, if we have a 10 Watt transmitter, or 40 dBm, we need to bring that signal down to a maximum of -67 dBm. In other words we need at least 107 dB of attenuation and if we have a safety margin of two, we'll need 110 dB of attenuation, remember, double power means adding 3 dB. <p> So, find 110 dB of attenuation. As it happens, if I connect most of my attenuators together, I could achieve that level of attenuation, but there's one further issue that we'll need to handle and that's power. <p> As you might recall, an attenuator has several attributes, the most obvious one is how much attenuation it brings to the party. It's specified in dB. My collection of attenuators range from 1 dB to 30 dB. Another attribute is the connector it comes with, I have both N-type and SMA connectors in my collection, so I'll need some adaptors to connect them together. One less obvious and at the cheap end of the scale, often undocumented, aspect of an attenuator is its ability to handle power. Essentially we're turning an RF signal into heat, so an attenuator needs to be able to dissipate that heat to handle what your transmitter is throwing at it. <p> I said that from a safety perspective I'd like to be able to handle 20 Watts of power. Fortunately we don't need all our attenuators to be able to handle 20 Watts, just the first one directly connected to the transmitter. If we were to use a 20 Watt, 30 dB attenuator, the signal through the attenuator is reduced to 0.02 Watts and the next attenuator in line only needs to be able to handle that power level and so-on. <p> To get started, find about 110 dB of attenuation, make sure it can handle 20 Watts and you can start playing. <p> Before you start keying up your transmitter, how might you handle a range of different transmitters and power levels and can you remove an attenuator when you test on a different frequency? <p> On that last point, let me say "No", you cannot remove the attenuator when you're measuring a different frequency. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Starting to measure spurious emissions ...
Foundations of Amateur Radio <p> At a recent local HAMfest we set-up a table to measure second and third harmonic emissions from any handheld radio that came our way. The process was fun and we learnt lots and in due course we plan to publish a report on our findings. <p> When we received a handheld, we would disconnect the antenna, and replace it with a short length of coax and connect it to a spectrum analyser. We would then trigger the Push To Talk, or PTT button and measure several things. We'd record the actual frequency and how many Watts that the transmitter was producing and then record the power level in dBm for the base frequency, double that frequency and triple that frequency. In other words, we'd record the base, second and third harmonics. <p> This resulted in a list of numbers. Frequency and power in Watts are obvious, but the three dBm numbers caused confusion for many visitors. The most perplexing appeared to be that we were producing negative dBm numbers, and truth be told, some positive ones as well, we'll get to those in our report. <p> How can you have negative power you ask? <p> As I've discussed before. A negative dBm number isn't a negative value of power, it's a fraction, so, -30 dBm represents 0.000001 Watts and you'd have to admit that -30 dBm rolls off the tongue just a little easier. <p> What we measured and logged was the overall transmitter output and at specific frequencies. As I've discussed previously, if you transmit using any transceiver, you'll produce power at the intended frequency, but there will also be unintended or unwanted transmissions, known as spurious emissions. <p> The International Telecommunications Union, or ITU, has standards for such emissions. In Australia the regulator, the ACMA, uses the ITU standard for radio amateurs, but I should point out that this might not be the case where you are. It's entirely possible, and given human diversity, probable even, that there are places where there are more stringent requirements, so bear that in mind. <p> I'll state the standard and then explain. <p> For frequencies greater than 30 MHz, the spurious emission must not exceed the lesser of 43 + 10 * log (power) or 70 dB. <p> That might sound like gobbledegook, so let's explore. <p> First thing to notice is that this is for transmissions where the transmitter is tuned to a frequency greater than 30 MHz, there's a separate rule for frequencies less than 30 MHz and the ITU also specifies a range of different limits for special purpose transmitters like broadcast radio and television, space services, and others. <p> Second thing is that the spurious emissions are calculated based on total mean output power. This means that your spurious emissions are considered in relation to how much power you're using to transmit and it implies that for some transmitters you can be in compliance at one power level, but not at another, so keep that in mind. <p> The phrase "the lesser of", means that from a compliance perspective, there's a point at which power levels no longer determine how much attenuation of spurious emissions is required. You can calculate that point. It's where our formula hits 70 dB, and that is at 500 Watts. In other words, to meet the ITU standard, if you're transmitting with less than 500 Watts, you're subject to the formula and if you're transmitting with more than 500 Watts, you're required to meet the 70 dB standard. <p> It means that, at least in Australia, spurious emissions for amateurs are dependent on transmitter power because the maximum permitted power is currently 400 Watts for an amateur holding a so-called Advanced License. <p> Now I'll also point out explicitly that the emission standards that the ITU specifies are for generic "radio equipment", which includes amateur radio, but also includes anything else with a transmitter. <p> One thing to mention is that spurious emissions aren't limited to the second and third harmonics that we measured, in fact they're not even limited to harmonics. If you're using a particular mode then anything that's transmitted outside the bandwidth of that mode is considered a spurious emission and there are standards for that as well. <p> As an aside, it was interesting to me that in many cases amateur radio is treated separately from other radio services, but the ITU considers our community just one of several spectrum users and it's good to remember that the entire universe is playing in the same sandbox, even if only some of it is regulated by the ITU and your local regulator. <p> So, let's imagine that you have a handheld radio that has a total mean power output of 5 Watts. When you calculate using the formula, you end up at 50 dB attenuation. In other words, the spurious emissions may not exceed -13 dBm. So, if your radio measures -20 dBm on the second harmonic, it's compliant for that harmonic, but if it measures -10 dBm, it's not. I should also point out that this is for each spurious emission. About half the radios we tested had a second harmonic that was worse than the third harmonic. <p> So, what does this mean for your radio? I'd recommend that you start reading and measuring. You'll need to measure the total mean power, and the signal strength at the base frequency and the second and third harmonic. I will mention that surprises might happen. For example, the Yaesu FT-857d radio I use every week to host a net appears to be transmitting with a power level that doesn't match its setting. At 5 Watts, it's only transmitting just over 2 Watts into the antenna, but at the 10 Watt setting, it's pretty much 10 Watts. <p> You also don't need a fancy tool like we were using. All these measurements are relative to each other and you could even use a $20 RTL-SDR USB dongle, but before you start transmitting into its antenna port, make sure you have enough attenuation connected between the transmitter and your dongle, otherwise you'll quickly discover the escape velocity of the magic smoke inside. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Gathering Data rather than Opinions ...
Foundations of Amateur Radio <p> There's nothing quite as satisfying as the click of a well designed piece of equipment. It's something that tickles the brain and done well it makes the hairs stand up on the back of your neck. <p> If time was on my side and I wasn't going somewhere else with this, I'd now regale you with research on the phenomenon, I'd explore the community of people building mechanical keyboards and those who restore equipment to their former glory, instead I'm encouraging you to dig whilst I talk about the second and third harmonics. This is about amateur radio after all. <p> Over the years there has been a steady stream of commentary around the quality of handheld radios. Some suggest that the cheaper the radio, the worse it is. Given that these kinds of radios are often the very first purchase for an aspiring amateur it would be useful to have a go at exploring this. <p> When a radio is designed the aim is for it to transmit exactly where it's intended to and only there. Any transmission that's not where you plan is considered a spurious emission. By carefully designing a circuit, by adding shielding, by filtering and other techniques these spurious emissions can be reduced or eliminated, but this costs money, either in the design stage, or in the cost of materials and manufacturing. It's logical to think that the cheaper the radio, the worse it is, but is it really true that a cheap radio has more spurious emissions than an expensive one? <p> To give you an example of a spurious emission, consider an FM transmitter tuned to the 2m amateur band, let's say 146.5 MHz. If you key the radio and all is well, the radio will only transmit at that frequency, but that's not always the case. It turns out that if you were to listen on 293 MHz, you might discover that your radio is also transmitting there. If you're familiar with the amateur radio band plan, you'll know that 293 MHz is not allocated as an amateur frequency, so we're not allowed to transmit there, in fact, in Australia that frequency is reserved for the Australian Department of Defence, and there's an additional exclusion for the Murchison Radio-astronomy Observatory. <p> 293 MHz isn't a random frequency. It's twice 146.5 MHz and it's called the second harmonic. <p> There's more. If you multiply the base frequency by three, you end up at 439.5 MHz, the third harmonic. In Australia, that frequency falls into the amateur allocation as a second use, its primary use is again the Department of Defence. <p> These two transmissions are examples of spurious emissions. To be clear, the transmitter is tuned to 146.5 MHz and these unintended extra signals come out of the radio at the same time. <p> This is bad for several reasons, legal and otherwise. The first, obvious one, is that you're transmitting out of band, which as an amateur you already have no excuse for, since getting your license requires you to understand that this is strictly not allowed. <p> The International Telecommunications Union, or ITU, has specific requirements for what's permitted in the way of spurious emissions from an amateur station. <p> Spurious emissions also mean that there is energy being wasted. Instead of the signal only coming out at the intended frequency, some of it is appearing elsewhere, making the 5 Watts you paid for less effective than you hoped for. <p> So, what's this got to do with the click I started with? <p> Well, thanks to Randall, VK6WR, I have on loan a heavy box with a Cathode Ray Tube or Green CRT screen, lots of buttons and knobs and the ability to measure such spurious emissions. It's marked "HP 8920A RF Communications Test Set". Using this equipment is very satisfying. You switch it on and a fan starts whirring. After a moment you hear a beep, then the screen announces itself, almost as-if there's a PC in there somewhere - turns out that there is and the beep is the Power On Self Test, or POST beep. Originally released in 1992, this magic box can replace 22 instruments for transceiver testing. I started downloading user manuals, oh boy, there's lots to learn. Bringing back lots of memories, it even has a programming language, Instrument BASIC, to control it. Where have you been all my life? Turns out that in 1992 this piece of kit cost as much as my car. Anything for the hobby right? <p> At the next HAMfest I'll be using it to measure as many handhelds as I can get my hands on and taking notes. I have no idea how many I'll be able to test, but I'm looking forward to putting some numbers against the repeated claims of quality and price. I can tell you that a couple of weeks ago I got together with Randall and Glynn VK6PAW and spent an enjoyable afternoon testing several radios and there are some surprising results already. <p> Perhaps this is something you might attempt at your next community event, gather data, rather than opinions... <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Jumping into the unknown ...
Foundations of Amateur Radio <p> If you walk into your radio shack and switch on a light, the result is instantaneous, one moment it's dark, the next it's not. What if I told you that as immediate as it appears, there is actually a small delay between you closing the circuit and the light coming on. Likely the distance between your switch and your light is less than say 10 meters, so the delay is likely to be less than 33 nanoseconds, not something you'd notice unless you're out to measure it. <p> What if your light switch is 3,200 km away? That's the length of the first transatlantic telegraph cable in 1858. <p> Let's start with the notion that between the action of closing a switch, or applying a voltage at one end of the cable and it being seen at the other end takes time. If we ignore the wire for a moment, pretending that both ends are separated by vacuum, then the delay between the two ends is just over 10 milliseconds because that's how long it takes travelling at the speed of light. One of the effects of using a cable is that it slows things down. In case you're curious, the so-called Velocity Factor describes by how much. A common Velocity Factor of 66 would slow this down by 66%. <p> This means that there is a time when there is voltage at one end and no voltage at the other. <p> There are a few other significant and frequency dependent things going on, we'll get to them, but before we go any further, it's important to consider a couple of related issues. <p> Ohm's Law, which describes the relationship between voltage, current and resistance in an electrical circuit was first introduced in 1827 by Georg Ohm in his book: "The Galvanic Chain, Mathematically Worked Out". Initially, his work was not well received and his rival, Professor of Physics Georg Friedrich Pohl went so far as to describe it as "an unmistakable failure", convincing the German Minister for Education that "a physicist who professed such heresies was unworthy to teach science." <p> Although today Ohm's Law is part and parcel of being an amateur, it wasn't until 1841 that the Royal Society in London recognised the significance of his discovery, awarding the Society's oldest and most prestigious award, the Copley Medal, in recognition for "researches into the laws of electric currents". <p> I'll point out that Ohm only received recognition because his work was changing the way people were starting to build electrical engines and word of mouth eventually pressured the Royal Society into the formal recognition he deserved. <p> I also mentioned the speed of light in relation to the delay between applying a voltage and it being seen at the other end, but it wasn't until 1862 when James Clerk Maxwell published a series of papers called "On Physical Lines of Force" that light speed was actually derived when he combined electricity and magnetism and proved that light was an electromagnetic wave, and that there were other "invisible" waves, which Heinrich Rudolph Hertz discovered as radio waves in 1888. <p> How we understand transmission lines today went through a similar discovery process. Your radio is typically connected to an antenna using a length of coaxial cable, which is a description for the shape the cable has, but the nature of the cable, what it does, is what's known as a transmission line. <p> If you looked at the submarine telegraph cable of 1858, you'd recognise it as coaxial cable, but at the time there wasn't much knowledge about conductance, capacitance, resistance and inductance, let alone frequency dependencies. James Clerk Maxwell's equations weren't fully formed until 1865, seven years after the first transatlantic telegraph cable was commissioned and the telegraph equations didn't exist until 1876, 18 years after the first telegram between the UK and the USA. <p> In 1854 physicist William Thomson, was asked for his opinion on some experiments by Michael Faraday who had demonstrated that the construction of the transatlantic telegraph cable would limit the rate or bandwidth at which messages could be sent. Today we know William Thomson as the First Lord Kelvin, yes, the one we named the temperature scale after. Mr. Thomson was a prolific scientist from a very young age. <p> Over a month, using the analogy with the heat transfer theory of Joseph Fourier, Thomson proposed "The Law of Squares", an initial explanation for why signals sent across undersea cables appeared to be smeared across time, also known as dispersion of the signal, to such an extent that dits and dahs started to overlap, requiring the operator to slow down in order for their message to be readable at the other end and as a result, message speed for the first cable was measured in minutes per word, rather than words per minute. <p> Today we know this phenomenon as intersymbol interference. <p> It wasn't until 1876 that Oliver Heaviside discovered how to counter this phenomenon using loading coils based on his description of what we now call the Heaviside condition where you can, at least mathematically, create a telegraph cable without dispersion. It was Heaviside's transmission line model that first demonstrated frequency dependencies and this model can be applied to anything from low frequency power lines, audio frequency telephone lines, and radio frequency transmission lines. <p> Thomson worked out that, against the general consensus of the day, doubling the line would actually quadruple the delay needed. It turns out that the length of the line was so significant that the second cable laid in 1865, 560 km shorter, outperformed the original cable by almost ten times, even though it was almost identical in construction, providing physical proof of Thomson's work. <p> It has been said that the 1858 transatlantic telegraph cable was the scientific equivalent of landing man on the Moon. I'm not sure if that adequately explains just how far into the unknown we jumped. Perhaps if we blindfolded Neil Armstrong whilst he was landing the Eagle... <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How fast is Morse code?
Foundations of Amateur Radio <p> The first official telegram to pass between two continents was a letter of congratulations from Queen Victoria of the United Kingdom to President of the United States James Buchanan on 16 August 1858. The text is captured in the collection of the US Library of Congress. It's a low resolution image of a photo of a wood engraving. Based on me counting the characters, the text from the Queen to the President is about 650 characters. IEEE reports it as 98 words, where my count gives 103 words or 95 words, depending on how you count the address. <p> Due to a misunderstanding between the operators at either end of the 3,200 km long cable, the message took 16 hours to transmit and 67 minutes to repeat back. If you use the shortest duration, the effective speed is just over one and a half Words Per Minute or WPM. That's not fast in comparison with speeds we use today. Until 2003, the ITU expected that emergency and meteorological messages should not exceed 16 WPM, that a second class operator could achieve 20 WPM and a first class operator could achieve 25 WPM. <p> To put the message speed in context of the era, in 1856, RMS Persia, an iron paddle wheel steamship and at the time, the largest ship in the world, won the so-called "Blue Riband" for the fastest westbound transatlantic voyage between Liverpool and Sandy Hook. The journey took nine days, 16 hours and 16 minutes. Similarly, it wasn't until 1861 that a transcontinental telegraph was established across the United States. In 1841 it took 110 days for the news of the death in office of President William Henry Harrison to reach Los Angeles. Today that distance is covered by a 39 hour drive, a 5 hour flight, and about 12 milliseconds on HF radio. <p> So, while the speed of the message might not be anything to write home about today, at the time it was world changing. <p> Speed in Morse code is measured in a specific way. Based on International Morse code, which is what I'm using throughout this discussion, if you send the word "PARIS" a dozen times in a minute and the next time starts right on the next minute, you officially sent Morse at 12 WPM. <p> Looking inside the message of the word "PARIS", it's made up of a collection of dits and dahs. If a dit is one unit of time, then the letter "a", represented by dit-dah, is six units long when you include the spacing. In total, the word "PARIS", including the space after it, is exactly 50 units long. When you send at 12 WPM, you're effectively sending 600 dit units per minute, or ten units or bits per second, each lasting a tenth of a second. <p> Unfortunately, there is not a one-to-one relationship between Morse speed and ASCII, the American Standard Code for Information Interchange, for a number of reasons. Firstly, Morse is made from symbols with varying lengths, where ASCII, the encoding that we really want to compare speeds with, has symbols with a fixed length. You cannot simply count symbols in both and compare their speeds, since communication speed is about what you send, how fast you send it, and how readable it is at the other end. <p> Thanks to Aiden, AD8GM, who, inspired by my initial investigation, shared the idea and python code to encode Morse dits, dahs and spacing using a one for a dit, one-one-one for a dah, and zeros for spacing. This means that the letter "e" can be represented by "10" and the letter "t" by "1110". <p> You can do this for the standard Morse word "PARIS" and end up with a combination of 50 zeros and ones, or exactly 50 bits. I've been extending the code that Aiden wrote to include other encoding systems. When I have something to show it will be on my GitHub page. <p> However, using Aiden's idea, we gain the ability to directly compare sending Morse bits with ASCII bits, since they share the same zero and one encoding. If you use standard binary encoded ASCII, each letter takes up eight bits and the six characters for the word "PARIS", including the space, will take up 48 bits. Given that I just told you that the Morse version of the same message takes up 50 bits, you could now smile and say, see, ASCII is faster - wait, what? <p> Yes, if you send the word "PARIS " using 8-bit binary coded ASCII it's two bits shorter than if you use Morse. Job done, roll the press, headline reads: "Morse is four percent slower than binary coded ASCII". <p> Not so fast grasshopper. <p> If you recall, American Morse code, the one that has Samuel Morse's name written all over it, was replaced by a different code, made by Friedrich Gerke which in turn was modified to become what we now know as International Morse code. <p> Ask yourself, why did Gerke change the code? It turns out that one of the biggest issues with getting a message across an undersea cable was decoding the message at the other end. Let me give you an example, using American Morse, consider the encoding of "e", dit, and "o", dit-extra-space-dit and now try sending the word "seed" across a noisy line. Did you convey "seed", or was it "sod". In other words, there is room for ambiguity in the message and when you're talking about commerce, that's never a good basis for coming to a mutually binding agreement. <p> It turns out that encoding needs to be more subtle than just creating a sequence of bits. <p> Something else to consider, 10 bits per second is another way of saying 10 Hz, as-in, this is not just switching, we're dealing with frequencies and because we're not sending lovely sinusoidal waves, from a signal processing perspective, a very horrible square wave, we're also dealing with harmonics, lots of harmonics, and more of them as we speed things up. <p> So, if you send binary coded ASCII and compare it to Morse code, will your message actually arrive? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Will the real inventor of Morse code please stand?
Foundations of Amateur Radio <p> Morse code is a way for people to send information across long distances. The code we use today, made from dit and dah elements is nothing like the code demonstrated and attributed to Samuel Morse in 1837. <p> Over years and with assistance from Professor of Chemistry Leonard Gail and Physicist Joseph Henry, then Professor of Literature, Samuel Morse, and mechanically minded Alfred Vail developed an electrical telegraph system that automatically moved a paper tape and used an electromagnet to pull a stylus into the paper and a spring to retract it, marking the paper with lines. The original system was only intended to transmit numbers, and combined with a dictionary, the operator could decode the message. The telegraph was able to send zig-zag and straight lines, transmitting the message "Successful experiment with telegraph September 4 1837". The system was enhanced to include letters, making it much more versatile. On the 6th of January 1838, across 4.8 km of wire, strung across a barn, the new design with letters and numbers was demonstrated. <p> To optimise the enhanced version of the code, Alfred Vail went to his local newspaper in Morristown, New Jersey, to count the movable type he found in the compositor's type-cases, and assigned shorter sequences to the most common letters. You might think that this explains the distribution of the codes we see today, but you'd be wrong. <p> The 1838 system used four different element lengths and varied the spacing inside a character. For example, the letter "o" was signified by two dits with a two unit space between them, where today it's represented by three dahs. The letter "p" was signified by five dits, today this represents the number "5", and the code didn't distinguish between "i" and "y", between "g" and "j", and between "s" and "z". <p> A decade later and an ocean away in Germany, writer, journalist, and musician Friedrich Gerke created the Hamburg alphabet, based on the work by Vail and Morse, it standardised the length of the elements and spacing into what we use today, the dit and the dah. He changed about half of the characters and also incorporated four special German characters, the umlaut version of A, O and U and the CH sound - pronounced like the sound for the composer "Bach" or the Dutch name "Benschop" - not to be confused with the CH in child, or the CK in clock, or the SH sound in shop. It was different in other ways. For example, the letter "i" and "j" had the same code. The code was optimised to be more robust across undersea telegraph cables. I'll be coming back to that before we're done exploring, but not today. If you want to skip ahead, the term you're looking for is dispersion. Gerke's code was adopted in 1851 across Germany and Austria and it is known as Continental Morse code. <p> By the time most of Gerke's code was adopted as the European Standard in 1865 as one of many agreements that mark the founding of the International Telegraph Union in Paris, only four sequences of the original 1838 code remained and only two of those, "e" and "h" were identical. Which means that although the idea that Morse code is based around English is often repeated, at this stage it's nothing more than a myth, which my previous word list and subsequent dictionary letter counts across over fifty languages confirm. <p> I'll mention that given Gerke's German heritage, I also made a letter count from a modern German dictionary and one from 1901 and found that the letter distribution in those two are very similar with only the letter "s" and "t" swapped between position four and five in the popularity contest stakes. The German letter Top-5 is "enrts" and the "o" is the 16th most popular letter. <p> Speaking of "o", one observation to make is that the new International Morse code contained the letter "o" as dah-dah-dah, it also contained the letter "p" as dit-dah-dah-dit. These two codes come from an 1849 telegraph code designed by physicist, inventor, engineer and astronomer Carl August von Steinheil. There is evidence suggesting that he invented a print telegraph and matching dot script in 1836, based around positive and negative pulses, rather than pulse duration. I'm purposely skipping over earlier telegraph systems built and used by Carl Friedrich Gauss, Wilhelm Edward Weber, and Steinheil, only because we're talking about Morse code, not the telegraph. <p> The 1865 ITU standard for International Morse code includes several accented letters, symbols for semi-colon, exclamation mark, chevrons and several control codes and both normal and short forms for numbers which merge all the dahs in any digit into a single dah. Many of these codes are not part of the official standard today. <p> I'll point out that over time, experienced telegraph operators learnt to decode dits and dahs based on sound alone, negating the need for paper. This translates directly into how we experience Morse in our hobby today, by tone only. <p> There is a much more detailed explanation on how the telegraph evolved in a book by Russel W. Burns called: "Communications: An International History of the Formative Years". Fair warning, there are many claims and counterclaims, including the possibility that someone else entirely, Harrison Gray Dyar, a Chemist, invented an electrochemical telegraph, using chemically treated paper to make marks, dits and dahs, and demonstrated it between 1826 and 1828 near a race track on Long Island. <p> I'm mentioning this because Samuel Morse is often attributed as the source of all things telegraphy, but the reality appears to be much more nuanced and, unsurprisingly, there are conflicting accounts depending on the source, including acceptance and repudiation that Alfred Vail was the inventor of what we now call Morse code. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Is Morse really built around the most popular letters in English?
Foundations of Amateur Radio <p> Thanks to several high profile races we already know that sending Morse is faster than SMS. Recently I started digging into the underpinnings of Morse code to answer the question, "Can you send Morse faster than binary encoded ASCII?" Both ASCII, the American Standard Code for Information Interchange and Morse are techniques to encode information for electronic transmission. One is built for humans, the other for computers. <p> To answer the question, which is faster, I set out to investigate. I'm using the 2009 ITU or International Telecommunications Union standard Morse for this. <p> Morse is said to be optimised for sending messages in English. In Morse the letter "e", represented by "dit" is the quickest to send, the next is the letter "t", "dah", followed by "i", dit-dit, "a", dit-dah, "n", dah-dit, and "m", dah-dah. <p> The underlying idea is that communication speed is increased by making the most common letter the fastest to send and so-on. Using a computer this is simple to test. I counted the letters of almost 400,000 words of my podcast and discovered that "e" is indeed the most common letter, the letter "t" is next, then "a", "o", and "i". Note that I said "letter". The most common character in my podcast is the "space", which in Morse takes seven dits to send. <p> Also note that the Morse top-5 is "etian", the letter "o" is 14th on the list in terms of speed. In my podcast it's the fourth most popular letter, mind you, my name is "Onno", so you might think that is skewing the data. <p> Not so much. <p> If I use the combined works of Shakespeare, and given that it represents an older and less technical use of language, and doesn't feature my name, I figured it might have a different result. The top-5 in his words are "etoai", the letter "o" is the third most popular, and "space" still leads the charge, by nearly 3 times. <p> I also had access to a listing of 850 job advertisements, yes, still looking, and the character distribution top-5 is "eotin", the letter "o" is the second most popular letter. <p> Because I can, and I'm well, me, I converted the ITU Morse Code standard to text and counted the characters there too. The top-5 letters are "etion", but the full stop is a third more popular than the letter "e", mind you that might be because the people at the ITU still need to learn how to use a computer, seriously, storing documents inside the "Program Files" directory under the ITU_Admin user, what were you thinking? I digress. The "space" is still on top, nearly six times as common as the letter "e". <p> As an aside, it's interesting to note that you cannot actually transmit the ITU Morse standard using standard Morse, since the document contains square brackets, a multiplication symbol, asterisks, a copyright symbol, percent signs, em-dashes, and both opening and closing quotation marks, none of which exist as valid symbols. <p> Back to Morse. The definition has other peculiarities. For example the open parenthesis takes less time to send than the closing one, but you would think that they are equally common, given that they come in pairs. If you look at numbers, "5" takes the least amount to send, "0" the longest. In my podcast text "0" is a third more common than "1" and "9" is the least common. In Shakespeare, "9" is the most common, "8" the least, and in job listings, "0" and "2" go head-to-head, and both are four times as common as the number "7" which is the least common. <p> All this to say that character distribution is clearly not consistent across different texts and Morse is built around more than the popularity of letters of the alphabet. For example, the difference between the left and right parenthesis is a dah at the end. If you know one of the characters, you know the other. The numerical digits follow a logical progression from all dits to all dahs between "0" and "9". In other words, the code appears to be designed with humans in mind. <p> There are other idiosyncrasies. Most of the code builds in sequences, but there are gaps. If you visualise Morse as a tree, the letter "e" has two children, both starting with a dit, one followed by another dit, or dit-dit, the letter "i", and the other, followed by a dah, dit-dah, the letter "a". Similarly, the letter "t", a dah, has two children dah-dit, "n" and dah-dah, "m". This sequence can be built for many definitions, but not all. The letter "o", dah-dah-dah, has no direct children. There's no dah-dah-dah-dit or dah-dah-dah-dah sequence in Morse. The letter "u", dit-dit-dah has one child "f", dit-dit-dah-dit, but the combination dit-dit-dah-dah is not valid Morse. <p> It's those missing combinations that led me to believe that Morse isn't as efficient as it could be and what originally led me to investigate the underpinnings of this language. <p> I think it's fair to conclude at this point that Morse isn't strictly optimised for English, or if it is, a very small subset of the language. It has several eccentricities, not unlike the most popular computer keyboard layout, QWERTY, which wasn't laid out for humans or speed typing, rather the opposite, it was to slow a typist down to prevent keys from getting in each other's way when there was still a mechanical arm punching a letter into a page. <p> In other words, Morse code has a history. <p> Now I'm off to start throwing some CPU cycles at the real question. Is Morse code faster than binary encoded ASCII? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Adventures with Morse Code
Foundations of Amateur Radio <p> If you've ever looked at Morse Code, you might be forgiven if you conclude that it appears to be a less than ideal way of getting information from point A to point B. The idea is simple, based on a set of rules, you translate characters, one at a time, into a series of dits and dahs, each spaced apart according to the separation between each element, each character and each word. <p> The other day I came across a statement that asserted that you could send Morse faster than binary encoded ASCII letters. If you're not sure what that means, there are many different ways to encode information. In Morse, the letter "e" is the first character, represented by "dit", the letter "t" is the second character, represented by "dah". In ASCII, the American Standard Code for Information Interchange, the letter "e" is the 69th character, represented by 100 0101. The letter "t" is number 84 on the list, represented by 101 0100. <p> A couple of things to observe. The order of the characters between Morse and ASCII are not the same. That doesn't really matter, as long as both the sender and receiver agree that they're using the same list. Another thing to notice is that in Morse, letters are encoded using dits and dahs and appropriate spacing. In ASCII, or technically, binary coded ASCII, the letters are encoded using zero and one. <p> I'll also mention that there are plenty of other ways to encode information, EBCDIC or Extended Binary Coded Decimal Interchange Code was defined by IBM for its mainframe and mid-range computers. It's still in use today. In EBCDIC, the letter "e" is 133 and the letter "t" is 163. It was based around punched cards to ensure that hole punches were not too close together. It was designed for global use and can, for example, support Chinese, Japanese, Korean and Greek. Another encoding you might have heard of is UTF-16, which supports over a million different characters including all the emojis in use today. <p> Before I continue, I must make a detour past the ITU or the International Telecommunications Union. The ITU has a standard, called "Recommendation M.1677-1", approved on the 3rd of October 2009, which defines International Morse code. I'm making that point because I'm going to dig deeper into Morse and it helps if we're talking about the same version of Morse. I have talked about many versions of Morse before, so I'll leave that alone, but I will point out a couple of things. <p> The ITU defines 56 unique Morse sequences or characters. The obvious ones are the letters of the alphabet, the digits and several other characters like parentheses, quotes, question mark, full-stop, and comma, including the symbol in the middle of an email address, which it calls the "commercial at symbol" with a footnote telling us that the French General Committee on Terminology approved the term "arobase" in December 2002, but it seems that seven years isn't enough time to convince the ITU to update its own standard, mind you, the rest of the world, well, the English speaking part, calls it "at", the letter "a" with a circle around it, as in my email address, cq@vk6flab.com. <p> Another thing to note is that this standard is only available in English, Arabic, Chinese, French and Russian, so I'm not sure what the Spanish, Hindi, Portuguese, Bengali and Japanese communities, who represent a similar population size do for their Morse definitions. It's interesting to note that as part of its commitment to multilingualism, the ITU actually defines six official languages. Specifically, the "Spanish" version of the standard appears to be missing. <p> There's other curious things. For example, the standard defines a special character called "accented e", though it doesn't describe which accent, given that there are four variants in French alone, I found at least seven versions and it completely ignores accents on the i, the c, the o, special character combinations like "sz" in German and "ij" in Dutch. This isn't to throw shade on Morse, it's to point out that it's an approximation of a language with odd variations. I'm also going to ignore capitalisation. In Morse there's none and in ASCII, there are definitions for both, capitalised and not. <p> In addition to things you write in a message, there's also control codes. The ITU defines six specific Morse control codes. Things like "Understood", "Wait", and "Error". ASCII has those too. The first 31 codes in ASCII are reserved for controls like "linefeed", "carriage return", and "escape". <p> There are other oddities. The ITU specifies that the control code "Invitation to transmit" is symbolised by dah-dit-dah. If you're familiar with Morse, you'll know that this is the same as the letter "k". The specification says that multiplication is dah-dit-dit-dah, which is the same as "x". There's also rules on how to signify percentages and fractions using dah-dit-dit-dit-dit-dah, the hyphen, as a separator. <p> At this point I haven't even gotten close to exploring efficiency, but my curiosity is in overdrive. Is Morse really optimised for English, or are there other forces at work? I'm already digging. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The nature and ownership of information
Foundations of Amateur Radio <p> Have you ever made an international contact using amateur radio and used that towards tracking an award like for example the DXCC? If you're not familiar, it's an award for amateurs who make contact with at least 100 "distinct geographic and political entities". <p> In 1935 the American Radio Relay League, or ARRL published an article by Clinton B. DeSoto, W1CBD, titled: "How to Count Countries Worked: A New DX Scoring System". In the article he asks: "Are Tasmania and Australia separate countries?" <p> In case you're wondering, Tasmania has, at least in legal terms, been part of Australia since Federation in 1901. Not to be confused with New Zealand, a separate country over 4,000 kilometres to the east of Australia, Tasmania is the island at the south eastern tip of Australia. It was previously called the Colony of Tasmania, between 1856 and 1901 and before that it was called Van Diemen's Land between 1642 and 1856. Before then it was inhabited by the palawa people who lived there for about 42,000 years. They eventually became isolated after being cut off from the mainland by the Bass Strait when about 10,000 years ago sea levels rose due to the ice age coming to an end. In the last remaining local Aboriginal language 'palawa kani' it appears to have been called 'lutruwita' (/lu-tru-wee-ta/), but no living speakers of any of the original Tasmanian languages exist. As audio evidence, we have a few barely audible sounds spoken by Fanny Cochrane Smith on a wax record from 1899 on which she sang traditional songs. <p> I'm mentioning this to illustrate that DeSoto asking the question: "Are Tasmania and Australia separate countries?" is, in my opinion, fundamentally misguided. More so because of an island, well, rock, Boundary Islet, that's split by a border, one half belonging to Victoria, the other half to Tasmania. Specifically, since 1825, the state of Victoria and the state of Tasmania share a land border thanks to a survey error made in 1801. If you're into Islands on the Air, or IOTA, it's part of the Hogan Island Group which for activation purposes is part of the Furneaux Group, which has IOTA designation OC-195. <p> One point to make is that today the DXCC does not mention Tasmania, either as a separate entity, or as a deleted entity. It was removed from the DXCC in 1947. <p> The DXCC list is pretty famous in amateur radio circles. It's not the only such list. I already mentioned the IOTA list which contains a list of islands and island groups and their IOTA designation. There's also a list of 40 groups of callsign prefixes called CQ zones, published in CQ magazine, and a list of IARU regions maintained by the International Amateur Radio Union. There's also an ITU zone list, maintained by the International Telecommunications Union. <p> Each of these lists are essentially grouped collections with an attached label. <p> The list of DXCC entities is copyrighted by the ARRL. If you want to use it for anything other than personal use you need to ask permission. In other words, if you write software that for example tracks amateur radio contacts and you make that software available for others to use, you officially need permission from the ARRL to use it to track a DXCC. If you're an amateur outside of the United States your peak body will need permission from the ARRL to issue any DXCC award. <p> The ITU, the International Telecommunications Union is a United Nations specialised agency, part of our global community, owned by all humans. It peppers its content with copyright notices. The same is true for the International Amateur Radio Union, the IARU, the global representative body of all radio amateurs. It too peppers its content with copyright notices, even going so far as to add requirements that "(a)ny copy or portion must include a copyright notice" and that "(i)t is used for informational, non-commercial purposes only". <p> Let me ask you a question. <p> Can you achieve a DXCC without international cooperation? <p> Of course not. If you are an American amateur and want to get an award for contacting 100 distinct geographic and political entities, you can only do so by making contacts outside the United States of America. <p> As an Australian however, I have, according to the February 2022 version of the DXCC list, 340 countries to choose from, only one of which is the United States of America, and Alaska isn't part of the United States, apparently. <p> It might appear that I'm singling out the ARRL, but that's not true. CQ Communications, Inc. owns the list of CQ Zones, the ITU owns the list of ITU zones, the IARU owns the list of IARU Regions, Islands On The Air Ltd. and the Radio Society of Great Britain own the IOTA list and Clinton B. DeSoto W1CBD became a silent key in 1949, his copyright expired in 1999. <p> So, is grouping and labelling things sufficient to actually claim copyright? Can I claim copyright for all countries starting with the letter 'A' and calling it the 'Alpha Amateur Award'? My preliminary list for the 'Alpha Amateur Award' includes Afghanistan, Albania, Algeria, Andorra, Antigua, Argentina, Armenia, Australia, Austria and Azerbaijan and because it's not part of the United States, Alaska. Which reminds me, to encourage amateur radio activity in continents that need more, I'll add Africa and Antarctica. Consider that the 2023 edition of the triple A. <p> A bigger question to ask is: "Why should I need permission to use any of these lists?" <p> Can I create a public repository on GitHub that has all these lists in a single place, so others could use them without needing to hunt? What if I wanted to reformat and reuse these lists to create an online service to show the relationship between each of these lists for use by all radio amateurs? What if I wanted to charge a subscription fee to pay for the service? What if I wanted to roll out a whole company behind it and pay people to maintain it? <p> I'm all for people creating things and receiving credit, but at some point we start to take away from the community instead of giving back to it. Are these lists really owned by the various organisations claiming copyright and requiring written permission for their use, or do they belong to all radio amateurs? <p> Oh, the 'Alpha Amateur Award' list is copyleft. Look it up. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Asking a professional in the community...
Foundations of Amateur Radio <p> In the earlier days of my career I worked in a computing centre at a university surrounded by people with different interests and experiences in computing. There were programmers, hardware engineers, technicians, sales people, administrators, educators, support staff, statisticians and even a librarian. <p> There wasn't a lot of socialising or foosball, but every now and then we'd bump into each other in the lunchroom and talk about things that were not work related. During such conversations I learnt that people had all manner of interests outside their work, they were volunteer firefighters, or building their house, or active in the girl guides and any number of other unrelated pursuits and skills. <p> That same is true for the people inside the hobby of amateur radio. I've met people who were submariners, tow-truck drivers, accountants, paramedics, radio astronomers, telco and broadcast engineers, doctors, IT people, lots of IT people, and plenty of other professions. <p> As you might know, I'm self-employed. I am now acutely aware of mixing business with pleasure because not that long ago, every single time I met another person outside my field I'd get asked about some or other computer problem. Similarly I've witnessed medical professionals being asked about specific and personal medical issues and every time I experienced it or noticed it, a little part of me shied away from either telling people what I did or asking others for professional advice. <p> Now before you think that I'm telling you not to talk about computers within earshot of me, that's not at all what this is about. It's about building an awareness that there are people in your community from all kinds of different backgrounds with different experiences, something which I've talked about many times before, but, and here's a new thing, some of those people do not want to give free professional advice, or be dragged kicking and screaming back into their day-job when they're out having fun. <p> There's a difference between talking about what a virus is and asking about which computer to buy, a difference between talking about the neurological aspects of mushrooms and asking if someone can help you with deciding which medication to use. There's a difference between talking about radio telescopes and asking to access laboratory measuring equipment. <p> If you're unsure where the line is, think of it in this way. If your mate is a plumber, it's one thing asking them what sand in your sink means and another thing entirely to ask them to dig up your backyard. <p> I'm not telling you how to live your life, I'm asking you to be considerate of those around you who might have a skill set that you lack and need, whom you've met through the amateur community. <p> An example of how you might navigate this process is to ask the person if it's appropriate to ask a specific question and to be prepared for hearing "No". Or you might be surprised and find that they're happy to help, to a point. I'd encourage you to be mindful of that point. <p> In case you're wondering, nobody has been stepping on my toes and if you recently asked me a question, you haven't overstepped any lines. <p> At this point you might be wondering what this has to do with amateur radio and why I'm talking about it now. The answer lies in the nature and evolution of our community. If you look at us as we were a century ago, like I did extensively when I discussed the evolving nature of the so-called "Amateur's Code", apparently written in 1923 by Lieut.-Commander Paul. M. Segal, you'll know that the community from last century is nothing like the community today. <p> I'm sure that you agree that today we're not Gentlemanly, we're not beholden to the ARRL, and we're not all male, to name a few obvious changes and as a result the Amateur's code was updated, many times, to reflect our evolution. <p> Those changes came about because people had ideas, had discussions, wrote things down and shared them. That's what this is. A mark on the page saying that I'd like our community to be mindful of the expectations made of the members of the community around us. <p> Where are your boundaries and what did you do when someone stepped on them? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Planning and making lemonade
Foundations of Amateur Radio <p> The other weekend there was an amateur radio contest on. Not surprising if you realise that's true for most weekends. For a change, I knew about this contest before it started, because I missed out a year ago, so I did the smart thing to add it to my diary with an alert a month out. <p> In this particular contest there's points to be made by being a so-called roving station, that is, one that moves around during the contest and in the past that's how I've participated and had lots of fun. So the die was cast and a plan was concocted. <p> Being a rover meant that I would be outfitting my car with my radio. It's been out of the car for several years, taken out when we had the transmission replaced, and never actually returned. I started making lists of everything I'd need, including learning that you can use a bench top power supply to charge a 12V battery if your trusty charger has let the smoke out. I went hunting for the cable that connects the front of the radio to the back and realised that it was still in the car, so I could cross that off my checklist. <p> I decided for the first time that realistically I could log using paper and save myself the heartache of finding a computer with a suitable battery and matching software, especially since I'd be operating with low power so making a gazillion contacts wasn't going to be a problem. <p> I went to the shops to get some road food, in my case I like to bring water and oatmeal bars which keep me going through the night. One change was that the contest only ran for 24 hours, leaving less time for sleep. <p> I found my portable antenna tuner, plugged everything in, configured the radio for remote tuning, and tested it all on the bench in my shack. <p> In further preparation I packed my food, got a headlamp out, spare batteries, a pen and a spare, a ring binder for logging and my wristwatch to keep track of logging times. <p> The day before the contest I parked the car in the sun, extracted all the cables from behind the backseat, installed the radio, the battery, the head, the suction mount, the microphone, the speaker, the antenna tuner and antenna mount, and got everything where I wanted it. <p> In between rain showers I located the ropes I use to keep the antenna from breaking off the car when I'm driving, set it all up to length after hunting through the garage to find my multi-tap antenna to suit. Strapped that all together to the handhold in the cabin with a Velcro strap and called it a day. <p> The next morning I drove to my first activation location, installed the antenna on the 40m band, turned on the radio, tuned it, and called CQ Contest. Made my first contact about six minutes after I started. I was excited. Drove to the next location, made the next contact six minutes later. On a roll I drove to my third spot, where things came unstuck. <p> I spent the next two hours getting nothing. I changed both location and band, setting the antenna to 15m and after initially tuning once I couldn't get it to tune again. I spent an hour trying. Given that I wasn't far from home, I went back for a break and to pick up one piece of equipment that I should have packed when I started, my antenna analyser. <p> I tested the antenna and for reasons I still don't understand, it was only resonant on 19 MHz, not much good if you're trying to tune somewhere on 21 MHz. <p> I moved back to my first spot and changed to the 10m band. Three hours to the minute after my second contact, I made another one, this one outside the state. <p> By this time it had been raining steadily for four hours, despite a forecast of little or no rain. The car was stuffy, no way to open the window and stay dry, no contacts, no fun. I asked myself why I was doing this and decided that I'd learnt a valuable lesson and packed up and went home. <p> I did go out later in the afternoon to provide some moral support to a friend who had made double the three contacts I'd made, but by dusk we had both had enough. <p> My lesson for this week? Test the antenna before you go out and bring your analyser. I must add that I've been contesting for years and I've always packed the analyser but never ever needed it. This time I didn't and Murphy let me know that anything that can happen, will. <p> It might sound like a dejected wet cat story, but I learnt a valuable lesson and now I've got another challenge, to discover just why my trusty antenna stopped working. If I do find out I'll let you know. <p> What unexpected lessons have you learnt of late? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Where is your community and how resilient is it?
Foundations of Amateur Radio <p> During the week, prompted by a protest on popular social media site Reddit, I rediscovered that there are other places to spend time. It sounds absurd now, but until then much of my social interaction with the world was via a single online presence. This didn't happen overnight. Over the years more and more of my time was spent on Reddit engaging with other humans around topics of my interest, amateur radio being one of them. <p> As you might know, I'm the host of a weekly net, F-troop. It's an on-air radio discussion for new and returning amateurs that's been running since 2011 and you can join in every Saturday for an hour at midnight UTC. <p> In addition to the net, there's an online component. It captures items of interest shared during the on-air conversation. It's intended to stop the need to read out web addresses on-air, create a historic record of the things we talk about and allow people who are not yet amateurs to explore the kinds of things that capture our interest. <p> Since 2014, F-troop online was a website that I maintained. After the announced demise of the service in 2020 I explored dozens of alternatives and landed on the idea to move to Reddit, which happened in March of 2021. <p> At the time of selecting Reddit as the successor to the website, I wanted to create a space where anyone could add content and discuss it, rather than rely on a single individual, me, to update the website every time something was mentioned. During the net these days you'll often hear me ask a person to post that on Reddit. <p> This to illustrate, at a small scale, how the F-troop community shares its knowledge with each other and the wider community. <p> With the realisation that there are other places to spend time, comes an uneasy feeling about how we build our online communities, and how resilient they really are. <p> Before the Internet our amateur radio community talked on-air, or in person at club meetings, or shared their interests in a magazine, or wrote letters. Today we congregate online in many different communities. If one of those fails or loses favour, finding those people elsewhere can be challenging, especially if those communities prefer anonymity. <p> For quite some time now I have been thinking about how to build a radio amateur specific online community. The issues to surface, address and overcome are wide and varied. I created a list ... hands up if you're surprised ... I will point out that I'm sure it's incomplete, your additions and comments are welcome. <p> Funding is the first item to consider. All of this costs time and money. Amateurs are notorious for their deep pockets and short arms, but they're no different from much of humanity. If this community needs to endure, it needs to be financially sustainable from the outset. <p> Authentication and Identity is the next priority. If it's for amateurs, how do you verify and enforce that and what happens if an amateur decides not to renew their callsign, do they stop being an amateur? Should this community be anonymous or not? <p> Moderation and Content is next on the list. What types of content are "permitted"? What is the process to regulate and enforce it? <p> Is this forum public and accessible via a search engine, or private? Can people who are not yet amateurs benefit from the community and use it to learn? <p> How do you set rules of conduct and how do you update them? How do you deal with rule infractions and how do you scale that? <p> Who is this for? Is it decentralised across each callsign prefix, across a DXCC entity, or based on some other selection criteria? <p> Can you have more than one account, or only one per person, or one per callsign? <p> What about machine accounts, like a local beacon, repeater, solar battery, radio link, propagation skimmer or other equipment? <p> What about bots and APIs? If that doesn't mean anything, a bot, short for robot, is a piece of software that can do things, like mark content as being Not Safe For Work, or NSFW, or it could enforce rules, or look-up callsigns, or share the latest propagation forecast or check for duplicates, scale an image, convert Morse code, check for malicious links, or anything you might want in an online community. The way a program like a bot, or a mobile client, or a screen reader, or a desktop application talks to the community is using an API, or an Application Programming Interface. <p> Incidentally, the protest at Reddit is about starting to charge for access to the API, something which will immediately affect software developers and eventually the entire Reddit community, even if many don't yet realise this. <p> What about system backups and availability? How seriously are we taking this community? Is there going to be a Service Level Agreement, or are we going to run it on a best-effort basis? How long is it acceptable for your community to be inaccessible? <p> What about content archiving and ageing? Do we keep everything forever, do we have an archive policy? What happens if a topic that's permitted one year isn't permitted a year later? <p> And those are just to start the discussion. <p> There are plenty of options for places to start building another community, but will they last more than a couple of years, or be subject to the same effects that a Coronal Mass Ejection causes on HF propagation, being wildly random and immensely disruptive? <p> At the moment I'm exploring an email list as a place to store our F-troop data and I intend to discuss archiving it in the Digital Library of Amateur Radio and Communications. <p> Where is your online community and how resilient is it really? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What is our legacy?
Foundations of Amateur Radio <p> Our hobby has been around for over a century. The Wireless Institute of Australia, or WIA, is the oldest amateur association on the globe, having just marked 113 years since formation. The American Radio Relay League, or ARRL, is four years younger, founded in 1914. <p> I'm mentioning these two associations because they documented their journey through many of the years since foundation. The ARRL has published QST magazine since 1915 and the WIA has published Amateur Radio Magazine since 1933. <p> Before the Internet and the Digital Library of Amateur Radio and Communications, magazines like QST and AR Magazine were some ways of documenting and archiving achievements across our community. <p> If you find my professional biography online, you'll read: Experienced polyglot IT professional, software developer, trouble shooter, researcher, public speaker, educator, writer and publisher, founder and small business owner, podcaster, and licensed radio amateur. <p> It's fair to say that I've done a great many things across the technology arena. I have been writing software since before I was a teenager. At the time we used words like freeware and shareware, we copied lines of BASIC from the pages of the latest computer magazine, or recorded the TV teletext signal to access a programme. I recall typing pages of hexadecimal codes and running the result. Very satisfying to make sprites running across your screen. <p> In the decades since, technology has moved on. I've had a front-row seat to see that evolution happen. I've also witnessed one of the victims of the 1980's computer craze, the fundamental obliteration of its history. Much has been lost, either physically by destruction or disposal of boxes of magazines or the deterioration of audio cassette tapes once used to store software. I hold a Guinness World Record of Endurance Computing, set in 1989 during the Hobby Computer Club days, but you'll not find it anywhere other than a copy of the Dutch World Records that might be somewhere in my garage, or not. The twice-daily magazine we published over the three days of the event, Elephant News, was lost to time. <p> I'm mentioning this because this loss is not limited to the 1980's, it's happening here, today. As our hobby evolves into the software realm, we need to consider just how that legacy continues beyond our own lifetime. For example, we have lost access to the fundamentals of how exactly HAM DRM works, we've lost the source for VK Contest Logger to name another, and the collected designs by so-called antenna guru L.B. Cebik W4RNL (SK) are scattered around the Internet, but as far as I know, none of it is complete. <p> Fortunately we have tools at our disposal to keep our history. As I mentioned, the Digital Library of Amateur Radio and Communications or DLARC is an Internet Archive project to catalogue and store current and historic amateur media. In the 30 weeks since starting in October 2022, it now has 75,000 items and continues to grow under the expert stewardship of Program Manager, Special Collections, Kay, K6KJN. <p> The DLARC is not the only tool at our disposal and documentation isn't the only way we share technology in our hobby. More and more of what we do is based around software. We use programs to process signals, to generate and receive different modes, to create logs, to model antennas, to log propagation, and that list grows daily. <p> One of the most significant changes in software since my childhood is that of the introduction of Open Source Software in 1998. I've spoken about this several times before and I recently pointed at Not1MM as an example of an Open Source contest logger, but that is not the only project available. <p> If you visit GitHub.com and search for "amateur radio", you'll discover over a thousand projects showing a healthy ecosystem of activity from people like Daniel EA4GPZ who shared gr-satellites, a collection of telemetry decoders that support many different amateur satellites. <p> You'll find APRSdroid by Georg D01GL, which allows radio amateurs to view and report locations using the APRS network. <p> There's an Arduino based rotator interface by Anthony K3NG, an advanced ham radio logger called CQRLOG by Petr OK2CQR, a radio modem by Dan KF7IJB, remoteAudio by Tobias DH1TW, and the list goes on. <p> I must also point out that I'm only naming the person behind the repository because as is the whole point of Open Source software, anyone can contribute in different ways. You can make a copy of the source-code and write your own version, a so-called fork, or you can create trouble-tickets to explain a bug or problem, there's ways of contributing fixes and ideas and all of that can be done by anyone anywhere. Many of the projects I've just shared are a combination of years of effort by many different people. <p> And that is the point of this conversation. Amateur Radio is a collaborative affair. We learn and share from the experience of others. We document how we built a schematic, or an antenna, or managed to achieve some feat and share that with the rest of the community. <p> It's not limited to hobbyist projects either. I purchased my Analog Devices ADALM-Pluto SDR hardware specifically because it was Open Source and came with all manner of tools and code that I could tease apart, improve on and change to my own requirements. <p> As we make more and more use of technology in our hobby, we run the risk of repeating the mistakes of the 1980's if we don't start making our efforts public and accessible to the community at large. <p> Imagine what our hobby would look like if we stopped sharing our successes and failures. <p> So, next time you want to look at some software to use, a calculator to build, or a thing you've learnt, consider what a technology appropriate way to share that might be. <p> What tools do you use today and how many of them are Open Source? How much of what you do is accessible to others and what happens if you stop paying for the hosting fees on your website? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Accolades in Amateur Radio?
Foundations of Amateur Radio <p> Today I'd like to start with saying thank you to the Wireless Institute of Australia for awarding me the Brenda Edmonds Education Award "in recognition of outstanding service in the education of the Amateur Radio Community and advancement of licensees." <p> It's an unexpected honour and a thrill that leads me to a question about how we recognise the people around us. <p> Over the years I've been a member of around a dozen radio amateur clubs and associations. To my recollection, the only one who has ever said thanks, and in my case, more than once, is the Wireless Institute of Australia. <p> What of the other clubs? What about the clubs you're a member of, or the groups you meet-up, either for lunch or on the local repeater? What about when you go out on a field-day and set-up a barbecue? <p> I look around me and I see activity that goes back more than a century. It's fair to say that every member of the community benefits from that effort. Memes on social media notwithstanding, there is real labour and toil, love and heartbreak, success and failure all around you. <p> What process do you have in place to say thanks? <p> Now before you start handing out participation trophies to everyone who turns up, mind you, they did when others didn't, consider what saying thanks might look like in your community? <p> It could be a special QSL card, or a certificate sent in the mail that someone could hang on their wall. I'm not advocating for sending out monetary awards or trophies, or other such paraphernalia, I'm just asking you to consider who in your group is worthy of a thank you and what that might look like. <p> You should also think about what you're saying thank you about. Is it for output, for the number of laughs, the level of participation, how many new club members were signed up, how many contacts someone made, how much fund raising they achieved, how many radios they fixed or how many nets they hosted, or something else? <p> You can think about who in your community might serve as an example to strive for and name the award after them. It might be someone who is active right now, or it might be someone who has attained mythical status in the stories you tell each other around the campfire during an overnight activity. <p> No matter what you call it, what it's for, how often you award it, what you present and whom you present it to, consider that it's a formal way of saying thank you, from the group to the individual, from all of you to one person in particular. <p> Since starting F-troop, I've now hosted more than 600 weekly nets for new and returning amateurs, a feat which we recently celebrated with a morning breakfast on the local aptly named Wireless Hill, but I couldn't have done it without the local repeater group who maintains the repeater we use. I also couldn't have done it without the countless individuals who join in every week, or who quietly sit on the sidelines making sure that the various nodes scattered around the globe are up and running, or the people who did the catering and logistics for the event. <p> Looking back, for me that event represents a missed opportunity to say thank you, something which I intend to do something about in the near future. <p> So, ask yourself. When was the last time someone in your community received a thank-you for their contribution? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

A Linux contest logger ...
Foundations of Amateur Radio <p> As you might know I'm in the process of building a cross-platform, open source, contest logger. Right now that project is at the stage where there is a proof of concept that you can use and install as a progressive web app on any web browser. It's intended as a starting point for discussion. Note that this is a long way from the stage where you might want to actually use it for any contest, it's not feature complete and if it breaks you get to keep both parts. It's currently cunningly named "contest-logger". No doubt that will change. <p> I'm collecting suggestions for features using the GitHub issue tracker, which you're welcome to contribute to. Behind the scenes, I'm writing the documentation that describes how I want to actually develop and design this application. What kinds of things are important, what will drive the process, all the planning stuff that sets up the project. Of course I'm doing this whilst writing articles, looking for work and dealing with the health-care fun and games associated with being alive. <p> While my project is nowhere near finished, truth be told, it really needs to start first, I've come across a different tool written by a fellow amateur Michael K6GTE. <p> This tool is written for Linux only in Python and is in Beta release at this point. This means that you can install and run the application and most of the functionality works. <p> The application is called Not1MM. <p> Here's what Michael has to say about his efforts: <p> Not1MM's interface is a blatant ripoff of N1MM. It's NOT N1MM and any problem you have with this software should in no way reflect on their software. <p> If you use Windows you should run away from this and use some other program. <p> I personally don't. While it may be possible to get N1MM working under Wine, I haven't checked, I'd rather not have to jump through the hoops. <p> Currently this exists for my own personal amusement. Something to do in my free time. While I'm not watching TV, Right vs Left political 'News' programs, mind numbing 'Reality' TV etc... <p> Michael goes on to say that: <p> The current state is "BETA". I've used it for a few contests, and was able to work contacts and submit a cabrillo at the end. I'm not a "Contester". So I'll add contests as/if I work them. I'm only one guy, so if you see a bug let me know. I don't do much of any Data or RTTY operating. This is why you don't see RTTY in the list of working contests. The Lord helps those who burn people at the... I mean who help themselves. Feel free to fill in that hole with a pull request. <p> You can find Not1MM on Michael's GitHub repository ready for your testing and experimentation. It's also available as a PyPi package if you're already familiar with Python. <p> In my opinion, one thing that this tool does well is consider how contest logging can be customised for individual contests and likely it will serve as inspiration for how I intend to implement the plugins in my own project. <p> I've also submitted a patch to Not1MM so you can use Docker to install it on your own machine or at least see what the requirements are to make it run in your environment. <p> I'm thrilled to have discovered this tool and hope that it solves some of your contest logging issues on your Linux workstation. <p> What features are you hanging out for in your contest logging adventures? Feel free to share your bug reports and feature requests to either Michael's project, or mine, or both. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Considering the language of our community ...
Foundations of Amateur Radio <p> A curious thing happens when you become part of the amateur community, you start to talk like an amateur. This phenomenon isn't specific to being a radio amateur, it happens whenever you join any community. Lead by example, one word at a time, you start to inherit a vocabulary that represents that community. Amateur radio, rife with acronyms and so-called Q-Codes, a standardised set of three-letter codes that start with the letter "Q", does this in spades. <p> If you've been around amateurs for more than 30 seconds, it's likely that you have already heard QSL, QTH and QRM, colloquially short for "Yup", "Home" and "Noise". There's an official meaning if you're keen. You can use the three letters as both a question and an answer, so QSL can mean "Can you acknowledge receipt?" and "I am acknowledging receipt." <p> Similarly, QTH means "What is your position in latitude and longitude (or according to any other indication)?" and QRM means "Is my transmission being interfered with?" <p> In those cases, used either with Morse code or Voice, they can make getting the message across simpler, faster, and more accurate, all important aspects of communication. It's easier to get QTH across to an amateur who doesn't speak English as their first language than it is to ask the whole question. <p> Other letter groups also creep into common language of an amateur. You've likely heard the letters: "XYL", but if you haven't, let me explain. Given that amateur radio is an activity dominated by men, "YL" refers to Young Lady and "XYL", refers to eX-Young Lady, a less than complimentary way of referring to one's wife. <p> I'd like to point out something curious. <p> In Morse code, XYL is sent using: -..- -.-- .-.. <p> It's intended to represent the word WIFE which is sent in Morse code as: .-- .. ..-. . <p> Now, if you know anything about Morse, you'll know that a dit is one unit, a dah is three. Individual elements are spaced by one unit. The space between letters is three units and the space between words is seven units. <p> Armed with that knowledge, XYL takes 39 units and WIFE takes 31 units to send. <p> So, sending the shortcut actually takes longer and it's clear that this choice is not about efficiency. Describing someone as an eX-Young Lady to refer to your Significant Other seems very 1950's to me. In the situation where you are the female amateur operator, the apparently appropriate way to refer to your Significant Other is as Old Man or "OM". Are female operators supposed to refer to themselves as YL or XYL? Really? <p> Sexism aside, this is extremely offensive in a same-sex and gender fluid community. <p> Then there's the symbol "88", apparently meant to refer to "Hugs and Kisses", not something I'd feel comfortable sending to anyone other than my partner who is emphatically not an amateur, let alone the idea that it would be appropriate to send it to any random station or the connotations around males sending such a message to a random female operator. <p> So, given that we now live in the 21st century and we're no longer in 1950, perhaps it's time to consider what language we teach new amateurs. <p> One proposal by Chris M0YNG is to refer to the Operator as "OP" and the Significant Other as "SO". Seems like a good start. <p> I will point out that this conversation was brought to my attention by Andreas DJ3EI who was participating in a Mastodon.radio conversation with Tim N7KOM who started the thread. <p> I think it's a worthwhile thing to discuss such an evolution of our language, it goes to the heart of our community, you are what you say you are, and words matter. <p> So, what words, acronyms and symbols do you use in your amateur community and what are you teaching new amateurs? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Measuring the Solar Flux Index at home ...
Foundations of Amateur Radio <p> Recently the Australian Space Weather Forecasting Centre issued an alert for a Coronal Mass Ejection or CME expected to impact Earth within 24 to 36 hours. This was presented within the context of seeing the resulting Aurora, but as a user of the HF radio spectrum, I'm subscribed to their email list, not for the pretty pictures, though I would be delighted to actually see them with my mark one eyeball, I'm on the list for the impact on propagation for my hobby. <p> As a good citizen I shared the alert with my community both via email and social media and as a result I received some questions and comments. One question was, "What does this mean?", one comment was "it's not going to impact the United States." <p> My response was to point out that HF propagation and the impact of the Sun is a very deep rabbit hole and encouraged further research by supplying several links, including a very detailed video by Rohde and Schwarz titled "Understanding HF Propagation", very, highly, recommended. <p> Whilst watching that video I discovered that the Solar Flux Index is measured using a receiver tuned to 2800 MHz or 2.8 GHz. Being in the business of having receivers scattered around my shack, I asked myself if I had something that was able to receive on that frequency. My RTL-SDR dongle doesn't cut it without extra hardware, it tops out at 1.75 GHz. However, my PlutoSDR has a standard frequency range that goes up to 3.8 GHz out - of the box - and with some tweaks can make it to 6 GHz, so well and truly within range. <p> Now, before I move on, I should mention that an RTL-SDR is a cheap, as-in $20, USB computer accessory that looks like a thumb-drive and is ostensibly built to receive digital television, or DVB-T signals. I've spoken about this previously. It can be used to receive radio frequencies outside the purpose it was built for. The PlutoSDR, or to give its official name the ADALM-PLUTO, on the other hand, something which I've also spoken about, is a single board Linux computer made by some smart people at Analog Devices, specifically for the purposes of learning and experimentation with receiving and transmitting RF. It comes with all manner of documentation and software and to be honest, I'm a little bit in love with mine. <p> Back to measuring stuff. In this case I'm attempting to measure the power levels of radio frequencies at 2.8 GHz. I know of a simple tool called rtl_power that can measure RF power over time and started investigating if that tool had been hacked to be able to use the PlutoSDR, rather than the RTL-SDR dongle. It might have been, but I've not yet discovered it, however, that in turn led me to several other tools, most of which I'm still investigating. <p> What it does tell me is that I'm not the first person to tread these paths, much has happened and been documented in the analogue sphere, some has been done using digital I/Q data and a transverter, a device that can multiply radio frequencies to make them appear in a different part of the radio spectrum, but I'm not yet sure if anyone has made a Solar Flux Index device out of a PlutoSDR. <p> I recalled a wonderful little tool that I've also talked about before, there's a theme here, I'm sure, but the tool, "csdr", written by Andras HA7ILM, which allows you to do all manner of interesting things to a stream of raw data, specifically RF raw data. It has a function called logpower_cf which Andras describes as "useful for drawing power spectrum graphs", which is precisely what I'm looking for. <p> Armed with that I'm now in the process of building a compiled version using Docker, so I can run csdr on my PlutoSDR and perhaps generate a power spectrum graph for 2.8 GHz. Of course that will now require that I learn how to extract raw data, known as I/Q data from the PlutoSDR command-line, process it through the logpower_cf function, output an image and hopefully show the result as a web-page. At the moment I'm still in the weeds with a Makefile, but that's not unusual. <p> Needless to say that I'm working on it and the result will no doubt turn up on my github page when it's done. In the most innocent terms possible, how hard can it be? <p> One takeaway that really needs to be expressed out loud, even if I've hinted at it. All the bits I've talked about here are things I've already been playing with. It wasn't until I came across a salient piece of information about the Solar Flux Index and how it was measured that all the puzzle pieces came together, the PlutoSDR, csdr, rtl-power, logpower_cf, the SFI and a web-server, that I could even imagine this happening. <p> The point being that even if you have all of the puzzle pieces in your hands, it might still take one missing piece of information for your brain to go "Ah-ha, wow, yes, this makes sense, I can do this." <p> So, keep collecting puzzle pieces, relevant to your own interests and one day you too will get to this point. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Propagation during the 2023 Solar Eclipse
Foundations of Amateur Radio <p> On Thursday the 20th of April, 2023 at 04:17:56 UTC the world was subjected to a rare event, a hybrid solar eclipse. In Perth I experienced a partial eclipse and people lucky enough to be directly in line, places like Ningaloo Reef, Exmouth and Barrow Island, experienced a total eclipse. Timor-Leste had the experience of the peak total eclipse. <p> At the time I went into my shack and refreshed the WSPR or Weak Signal Propagation Reporter beacon map I have open and noticed that my beacon wasn't reported. I sagely nodded my head, that makes sense, no Sun, no propagation and I got on with my life. <p> Last week a fellow amateur, Will VK6UU, asked if anyone had any VK6 specific HF propagation reports to make. Being the data geek that I am, I thought to myself, "Aha! I can do some data analytics on the WSPR dataset that I have." So, the die was cast for a few enjoyable hours of importing 2.4 gigabytes of compressed data into a database and constructing a set of SQL queries to see what I could learn. <p> Before getting stuck in, I spent a few hours thinking about the problem. How could I go about doing this? Propagation information is notoriously fickle. You have to consider the obvious things like the Solar Index and the Geomagnetic Index which vary considerably. Then there's the nature of the various reports themselves. Not everyone has their beacon on all the time, not everyone has their receiver on all the time. Weekends are more popular than weekdays and popularity overall is growing exponentially. The solar cycle is on the way to its peak, so there's that variation to consider and if that's not enough, how should you compare the Signal To Noise ratio between weak and strong beacons? <p> With all that in hand I set about constructing a plan. I created a folder to hold my charts and SQL queries, intent on uploading that to GitHub when the work was done. <p> For my very first test I thought I'd count the number of reports per band in a 24 hour window around the eclipse. I imported all the WSPR records that had a VK6 callsign, either as the transmitter or the receiver, given that I was interested in learning if stations transmitting from VK6 could be heard elsewhere and inversely, could VK6 stations hear any other stations? <p> As my first effort, I created a scatter-plot to get a sense of what kind of numbers I was looking at. The initial result was interesting. Around the eclipse itself there was no propagation. This wasn't unexpected, since that's what I'd seen on the day at the time on my own map. I changed my data to use a cumulative count per band to see if any band was particularly different and then discovered that there was no propagation at all, on any band. <p> That seemed ... odd. <p> So, I had a look at the source data and discovered a gap, which accounted for what my chart was showing. I added a fake record for the eclipse time itself, just so I could see where on the chart this gap was. Turns out that for VK6 stations, the gap is just over five hours, but it's not centred around the eclipse. There's a four hour window before the eclipse and a one hour window after it. <p> Then I started looking at all the reports from across the world. To give you a sense of scale, across April 2023 the dataset has nearly 139 million rows. It's 12 gigabytes in size. By contrast, in March of 2008 when the first reports started, there were just over 93 thousand reports in a 7 megabyte file. Charting this shows exponential growth, hitting a million reports in July of 2009, 10 million reports in January 2016 and 100 million reports in October of 2021. <p> So, the eclipse and global propagation. The results came in and the reports are that there was no propagation, on any band at any point during the just under two hours and 12 minutes before the eclipse and the 38 minutes following it. <p> That ... or the WSPRnet.org database was down during the eclipse. <p> So, unfortunately I cannot tell you what propagation was like during the eclipse, since it appears that those records don't exist. <p> Looks like we'll have to wait until 2031 when we can try this again. We'll all be a little older and wiser by that time and perhaps we can come up with a way to ensure that the global central WSPR data server is running without downtime, scaled to match the growing requirements and paid for by a benevolent organisation with deep pockets. <p> I did start considering making lemonade from my lemons and charting the kinds of down time the WSPR server has, but just looking over the various discussion groups showed that this is going to be painful. On the plus side, I learnt about SUM OVER and LAG functions in SQL, so there's that. <p> I must confess that if we're going to seriously use WSPR as a propagation analysis tool we need to fix these kinds of issues. I have no doubt that running WSPRnet.org is a massive enterprise and that it costs real time and money to make that happen. <p> So, who's up for the challenge and will the real owner of WSPRnet.org please raise their hand? <p> Finally, if by chance you were running a WSPR receiver during the 2023 Solar eclipse you might want to consider looking at sharing your logs, since they're potentially the only record still remaining. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Doing the same thing over and over again ...
Foundations of Amateur Radio <p> Over the years I've used the phrase, which I shamelessly stole, that amateur radio is a thousand hobbies in one. I've discussed countless different activities and adventures that all fall under the banner of amateur radio, in one way or another. <p> Since becoming a licensed radio amateur I've had the opportunity to speak with many different amateurs and hear their views on what amateur radio means to them. Based on their responses I've often found myself exploring new aspects of the hobby and discovering new and interesting ways to participate in this community. <p> Recently I put together a list of projects that are currently underway in my shack. I discovered that over time this list has evolved from physical radio activities, like portable activations, building antennas, camping, and going to HAMfests, the amateur radio version of a swap meet, into more computer related things like data analytics, writing software, fixing bugs and learning how the insides of a Software Defined Radio works. <p> That's not to say that I've given up on camping, or any of the other things, just that my priorities have shifted over time as I discover over and over again, just how big this hobby really is. <p> I mention this because one of the recurring observations I encounter is that others are doing the same thing day in and day out. That in and of itself isn't an issue, it's that they begin to describe that they're bored, that they've lost interest, that the hobby is in stagnation, that there's nothing new, that they're frustrated with their progress towards whatever goal they've set themselves. <p> For me, the key motivator in this hobby is learning. Everything else follows from there. That might not be your thing. You might be here for the emergency service aspect, or the hill climbing, the soldering and electronics. <p> It really doesn't matter why you're here at all. What keeps it fresh is trying new things. For example, if you're here for emergencies, have you set up a disaster event simulation in your community, or attempted to set-up your station 100 km from home and make contacts, using just the very basics? <p> If you're into soldering and electronics, have you ever designed your own circuit board, had it manufactured, or even manufactured it yourself, built the project and tested it? What about documenting it and making it available as a project for someone else? <p> If you've climbed all the hills in your state, have you tried doing this across the border, or overseas? What about testing with different antennas, or modes, power levels or logging tools? <p> The point being that it's easy to keep doing the same thing. What's harder, but potentially more rewarding, is to try something new and experience what happens. <p> One thing to keep in mind is that things will go wrong. That's where all the learning happens, so keep at it. <p> So, are you doing the same thing over and over again and expecting a different outcome, or are you excited like a newborn puppy, wagging your tail ready for the next adventure? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Why is radio regulated?
Foundations of Amateur Radio <p> One of the more perplexing things is the nature of radio regulation. If you're a licensed radio amateur, you'll be familiar with this idea, but if you're not it's bewildering and apparently absurd. <p> To explain, let me start with a light bulb that your neighbour put on their back porch. It's bright. It's pointing at your house. Like the apparent radiation from a gazillion suns it lights up the bedroom and sleep is hard to come by. Pretty annoying right? <p> As it happens, radio is a lot like that. If you know physics, it's exactly like that, but I'll ignore that for today. <p> In our modern world we have many different radios that each rely on a specific, let's call it colour, of light. In radio terms this is known as frequencies or radio bands and the entire collection is known as the radio spectrum. You've likely seen this without knowing. Your 2.4 GHz WiFi has an in-built frequency, 2.4 GHz, as does your 5 GHz WiFi. Your FM radio in the car has frequencies as well, 97.7 on the dial indicates 97.7 MHz. If you have an AM radio, 720 AM refers to 720 kHz. <p> Hidden in plain sight is why radio is regulated. Those numbers, 5 GHz, 2.4 GHz, 97.7 MHz and 720 kHz are all radio frequencies, or as I suggested, colours. Now imagine turning on a really bright light in the middle of that. All of a sudden your WiFi, FM and AM are wiped out. <p> It doesn't stop there. As I said, there are many different radios, and sources of radio frequencies. <p> Radio transmissions come from your mobile phone, Bluetooth headset, microwave oven, computer, television, remote control, key-less fob, power supply, car, power meter, solar panel, battery charger, LED light bulb, and the list goes on. Essentially anything electronic has a radio component. Some of these are transmitting unintentionally, like an electric motor or a switch mode power supply. Other things are transmitting on purpose, your microwave oven, your Bluetooth headset and your mobile phone. <p> As I mentioned, they're all sharing the same resource, the radio spectrum. <p> At this point you might ask about the impact of a single transmitter among all that. <p> Well, there are a few phenomena that you should know about. <p> Radio waves don't stop. They keep going. There's no boundary. To illustrate that, I have a tiny beacon, a transmitter, that every two minutes sends out a signal that shows my amateur callsign and location. It uses 10 milliwatts. To give you a sense of scale. A typical incandescent light bulb is about 60 Watts. My transmitter uses sixty thousand times less power. It has been heard 13,455 km away, about a third of the way around the planet. I will point out that different frequencies can be absorbed differently depending on how they're used, but you cannot rely on the idea that any radio frequency stops anywhere. <p> Another phenomenon is a thing called harmonics. Radio waves not only share the same space or spectrum, they're related to each other. Unless you take very specific precautions, a transmission made at 100 MHz, will be heard at 200 MHz, 300 MHz, 400 MHz, 500 MHz and so-on. While each of those transmissions gets progressively weaker, they still exist. Now imagine that someone else is using one of those other frequencies to communicate emergency information. It's like their backyard just got hit with a bright light. <p> To give you a specific example of why this can matter. Consider a radio amateur who uses 7 MHz. This is a licensed amateur radio frequency. Unless that amateur takes specific precautions, the 16th harmonic for 7 MHz is 112 MHz. If that doesn't mean anything to you, it's in the middle of the so-called air-band, frequencies used by aircraft around the planet to talk to each other and the ground. Very bad things could happen if safeguards weren't made. <p> As a result, radio is highly controlled and regulated. I'm not going into the laws or legalese here, given that this is a global phenomenon and the rules in their specifics are different in each country. There's a whole hierarchy of regulation, arrived at by international cooperation and agreement. <p> These regulations are not identical in each country, far from it. Each country has their interpretation of the rules and balances those with its own use of radio. For example WiFi, a very popular use of the radio spectrum, can be bamboozling in the endless variation of something so seemingly simple. <p> Most of this is invisible to most people. You go to the store and buy a WiFi base station and you go on your way. With the advent of online shopping, you can click "buy" on any window, regardless of which country the device comes from. If you're not careful your shiny new device, imported from somewhere is actually illegal in your country and fines and punishment can be severe. <p> If you start digging into this, you'll come across rules that for example say that you cannot change the antenna on a particular device. This is because the transmission power of the hardware is strictly regulated so it doesn't interfere with other users. Changing an antenna has the potential to change a number of aspects of your device. It can potentially amplify harmonics that were suppressed by the existing antenna. It could increase the perceived power level and overload other receivers. On a shared frequency it might lock out other users. This is why for example across the European Union, Private Mobile Radio on 446 MHz, or PMR446, a unlicensed radio provision that allows for business and personal use, has heavily regulated hardware. These devices are not permitted in places like Australia, the USA and Canada because in those countries, 446 MHz is used by radio amateurs and military radar systems. <p> This is why you'll find equipment like mobile phone amplifiers and jammers are heavily regulated and controlled. You'll also discover that transmitting on public frequencies like the FM broadcast band is a massive No-No. I'm not going into the so-called "FM capture effect", but the impact is that your personal transmitter needs to be locally louder than the station you're trying to break into and that in turn means that your little transmitter isn't so little any longer and the neighbours and the regulator will notice and come looking for you. <p> Before this begins to sound like I'm stopping anyone from experimenting, let me point out that licensed radio amateurs have been granted permission to experiment in this magical radio play ground. Of course there are very strict rules around this, but perhaps now there is an understanding on why that might be the case. <p> The more you dig in, the more stuff there is to explore and learn. As a radio amateur you are granted the keys to the city as it were. <p> If this information was shared with you after you asked a simple question, perhaps it's time to stop what you're doing, consider the impact on your wallet and equipment and in some cases freedom, and instead explore the idea of becoming a radio amateur where you can legally play with this stuff. <p> If you're already licensed, perhaps this will help to explain to others why. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The antenna system
Foundations of Amateur Radio <p> Several years ago I participated in a local contest. Over a 24 hour period I activated my mobile station in about 30 different locations. On my car, my vertical antenna screwed into a boot-lip mount connected to an antenna tuner or ATU, and my radio. I used rope to guy the antenna, threaded through the rear windows and held tight by closing the car boot. <p> Setting up consisted of parking the car, triggering the ATU to tune the antenna system and calling CQ. Moving to the next location consisted of driving there and setting up again. <p> Although this worked really well, I'm skipping over what I'm interested in exploring today. <p> The phrase "triggering the ATU to tune the antenna system" hides a lot of complexity. It was a surprise to me that there were several locations where the ATU just wouldn't tune. Despite my best efforts I was unable to get the system to a point where the radio was happy. In some cases I tuned off frequency and put up with a poor SWR. In others I physically had to move the car and park somewhere else. <p> In every case it was completely unknown if a particular location was going to be a problem. I recall for example parking in an empty nondescript car-park and having to drive around to find a location where my set-up would work. Afterwards I considered that the car-park was potentially built on top of an iron ore deposit, an old industrial area, or a pipe-line, all of which were a good possibility. <p> The point of this is that an antenna doesn't exist in isolation, it's called a system for a reason. We talk about the theoretical isotropic antenna and add disclaimers about that it cannot physically exist because it's infinitely small. One often overlooked aspect of an isotropic antenna is that it's in free space. <p> Free space is defined as space that contains no electromagnetic or gravitational fields and used as a reference. It's a theoretical place. On Earth there is no such thing, there's a planet under your feet, but even in outer space there are both gravitational and electromagnetic fields that impact on an antenna and its performance. <p> Staying nearer to home, recently we had a discussion about how close two antennas can be together. A suggested rule of thumb was that they need to be at least one banana or 30 cm away from each other. <p> Similarly when we erect a dipole, there's recommendations around needing to have it mounted more than half a wavelength over the ground. Some sources say higher. I'll ask the first obvious question. Is that dipole completely straight? In other words, should the centre be half a wavelength above the ground, or should the ends, and how far should the ends be from their mounts? <p> My point is that every antenna exists within the context of its environment and together it's a system. Some environments help the performance of your antenna system and some don't. Depending on frequency, this might not be the same for any location, or antenna design. <p> To be clear, an antenna system consists of the antenna, the feed line and the clips that hold it, the tuner, the radio and its power supply, the mount and the space around it, the radials, the tower, the pigeon poop on the wire, all of it. <p> Until recently my process to get any antenna to perform in a reasonable manner was to set it up, connect an antenna analyser, scan the appropriate range, tweak the antenna, scan again, rinse and repeat until it arrived at something approaching useful, or until it was good enough. <p> If you recall, I recently added some loading coils to a telescopic antenna to attempt to make it resonant on 10m, so I could connect my Weak Signal Propagation Reporter or WSPR beacon to it directly and leave it running independently from my main station. <p> I used the antenna analyser method, got it to the point where I had an antenna with a nice dip right at the required frequency and then watched it go completely sideways when I mounted the antenna in the window. <p> Having spent several hours getting to that point, I walked away and left it for another day. Today was that day. I again started on the floor of my shack and got nothing but an infinite SWR and no amount of tweaking could fix it. Right until the coax fell out of the SMA connector I was scratching my head. <p> After removing the faulty coax lead, I again tweaked the antenna and instead of using my antenna analyser, I fired up my NanoVNA, a tiny handheld open-hardware Vector Network Analyser or VNA. If you're not familiar, it's a standalone palm sized device with an LCD display and battery which will allow you to test most of your RF equipment. This little box came to me via a generous gift from a fellow amateur. It can repeatedly scan a range of frequencies and report in near real-time what's going on. Instead of waiting a minute after each adjustment, I could wait less than a second and immediately see the effect. <p> This has been a game changer. <p> I could mount the antenna against a metal surface and immediately see what the impact was. I could see the difference between it being mounted horizontally, where it would sag, to it being vertical where it stayed straight. I could see the steepness of the SWR plot, see how the low point moved around, up and down the band, see what the depth or lowest SWR was at any point. I could see my hand approaching the antenna, how nearby metal objects affect the antenna, what made it better and what made it worse. <p> The reason that I'm talking about this is because it's the very first time that I was able to actually get a feel for what affects an antenna, in what way and by how much. <p> To describe an analogy, it's like watching someone play a theremin and hearing how their hands affect the sound. If you're not familiar, a theremin is an electronic musical instrument controlled without physical contact by the performer, named after its inventor, Leon Theremin who patented it in 1928. From the outside it looks like a metal antenna that you bring your hands near to change the field. The changes are converted into sound. <p> The NanoVNA gives you the same level of feedback, but does so visually in a quantitative way, providing you with the insight to adjust your antenna to your liking and taking into account its entire environment. <p> Does this mean that I'm telling you to go out and buy one today? Well, that's not up to me, but I am intensely grateful for it arriving at my doorstep. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How much antenna is enough?
Foundations of Amateur Radio <p> When you start in this hobby one of the most frustrating aspects is that of selecting the right antenna. If you've been around for a while, you'll discover that this continues to be the case, even when you've been licensed longer than I've been alive. <p> In the past I've discussed at length why that is the case, but to recap, consider a dipole antenna. In essence it's two pieces of wire that are connected to the radio via some form of feed-line. <p> Now consider the idea of changing the length of each wire. You could trim each end in the same way, or you could make one end longer than the other. You could fold the ends at an angle, or you could mount the dipole near the ground, or high up in the trees, you could position it vertically, or arrange the wires at an angle towards each other. You could make the wire thicker, or thinner, from different material or arrange the ends so they meet up in a circle, or a square, a triangle or some other shape. <p> You get the point, there is endless variation arranging this single antenna and I've not even discussed things like feed-lines, traps, chokes, counterpoise and other RF shenanigans. <p> With that in mind, amateurs around the world are attempting to improve their antenna system every time they get on air to make noise. <p> Recently I reported that my 10 mW WSPR, or Weak Signal Propagation Reporter beacon was heard 13,455 km away in Sweden by Mats SM3LNM on the 10m band. The signal report was -25 dB, which means that with an experimental cut-off for a successful decode at -34 dB, I have 9 dB to play with, so at least theoretically, I could reduce my power even further, to 1 dBm, or just over 1 mW and still make the distance. <p> The antenna I'm using is one built by Walter VK6BCP (SK). It's a 40m vertical antenna, helically wound on a fibreglass blank and clamped to the side of a metal pergola. The antenna is tuned to the 10m band using an SGC SG-237 antenna coupler, essentially a device that can add or remove inductance or capacitance to make my antenna appear resonant on the appropriate frequency. The antenna coupler in turn is attached to about 20 or 30 meters of 75 Ohm, quad shield RG6 which I have left over from my remote internet satellite dish installation days. <p> That's all to say that the antenna system for my beacon is sub-optimal and it's likely that my actual power output is lower than the 10 mW that my beacon is reporting. <p> So, with all that in mind, what else could I try? <p> I have an indoor telescopic antenna stuck to the window and I've been wondering if I can attach my beacon to it directly and leave it running without the need to worry about disconnecting the beacon when I'm wanting to fire up my actual station to make other noises on air. <p> A quick scan with the analyser reveals that the lowest frequency out of the box is about 60 MHz. I decided that adding some loading coils might help, so I set about fabricobbling an antenna, yes, you heard me, fabricobbling, fabricating and cobbling together. <p> Anyway, using 7mm thick drip irrigation riser poly pipe as a form I wound two coils with 1.25mm copper wire that I had lying around. Depending on which calculator you used, that was either too much or not enough for my needs. I managed 53 windings, shy of the planned 60, but still a good start. <p> Using the same irrigation riser, which as luck would have it managed to match the thread for the telescopic antenna elements and feed point, I separated each element by about 100 mm from the feed point, then used the two loading coils to connect the feed point back to each element. An hour later I now have a telescopic antenna, with two loading coils and as luck would have it, I'm much closer. <p> The resonant point is now 30 MHz, down from 60 MHz, so I have a little more tinkering ahead of me. I might change the wire and use some eyelets at the ends to make assembly simpler, but the general idea seems to work as intended. <p> If it doesn't work, I've come across a design for a 25.5 meter long End Fed Half Wave antenna that will work on anything between 80m and 10m and it appears that my driveway is just long enough to fit, but that will negate the indoor aspect of the antenna. <p> All this reminds me of the ugliest dipole I ever saw, in a bush shack, a decade ago, consisting of two wires, haphazardly soldered onto a piece of coax, looped around an insulator, with a piece of wire holding it together, tied between two trees. It was only ever meant to be temporary, but it was there for years. I used it to speak to stations all over the pacific and in the process learnt a lot about the performance of both my radio and the antenna connected to it. <p> The point being that experimentation in antenna building is what we're all about, even going backwards from multi-band, high gain antenna farms, back to basics and exploration. <p> In case you're wondering, I haven't forgotten about the Hustler 6BTV antennas packed in boxes. They're still very much part of the grand plan, but in light of my recent low power experiments, I'm getting very curious about using antennas that really stretch the propagation friendship. Why? Because I can. <p> What antennas have you built that you were ashamed of? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Lost in space ...
Foundations of Amateur Radio <p> There is a fascination with space that arguably started long before the first time that human spaceflight was proposed by Scottish astronomer William Leitch in 1861. Names like Sputnik, Mercury, Gemini, Apollo and Columbia speak to millions of people and organisations like NASA, SpaceX and Blue Origin, to name a few, continue to feed that obsession. <p> In amateur radio we have our own names, things like ARISS, or Amateur Radio on the International Space Station, or its predecessor SAREX, the Shuttle Amateur Radio Experiment. <p> Today, stories about people making contact with the International Space Station continue to make news. We have school programs where amateur radio ground stations schedule a call to speak with an astronaut in space and we've been launching our own amateur satellites for a long time. Launched on the 12th of December 1961, OSCAR1, or Orbiting Satellites Carrying Amateur Radio was built by a group of California based amateur radio operators for 63 dollars. It operated for nearly 20 days, transmitting "Hi" in Morse on 144.983 MHz. <p> The first amateur radio space voice contact was made on the 1st of December 1983, almost forty years ago. <p> It's surprising that in the age of technology such a significant event has been so poorly recorded for posterity. <p> If you go searching for the actual audio, you'll discover several versions of this contact including varying transcripts. I've attempted to reconstruct the wording, but I've yet to hear a complete and unedited version. For example, there's an ARRL movie called "Amateur Radio's Newest Frontier" with out of sync audio. There's also an audio file with a transcript from an archived copy of a website by W7APD. The most recent one is on a video called "HAM - Official Documentary 2022", produced by students from the School of Visual and Media Arts program at the University of Montana and broadcast on Montana PBS on November 24th, 2022. <p> So, what follows is not necessarily complete, but calling from Space Shuttle Columbia it went a little like this: <p> "..U.S. west coast and calling CQ. Calling CQ North America. This is W5LFL in Columbia. In another 30 seconds I'll be standing by. Our spacecraft is in a rotation at the moment and we're just now getting the antenna pointed down somewhat more toward the Earth. So I should be able to pick up your signals a little bit better in the next few minutes. So W5LFL in Columbia is calling CQ and standing by. Go ahead." <p> "This is W5LFL in Colombia, W5LFL in Columbia, orbiting the Earth at an altitude of 135 Nautical Miles. Passing over the US West Coast and calling CQ. So W5LFL in Columbia is calling CQ and, ah, standing by. Go ahead." <p> "W5LFL on STS-9, WA1JXN, WA1 Japan X-Ray Norway, WA1JXN, Frenchtown Montana, WA1JXN standing by." <p> "Hello W1JXN, WA1 Juliet X-Ray November, this is W5LFL, I picked up your signals fairly weakly. I think our attitude is not really the best as yet, but you're our first contact from orbit. WA1 Juliet X-Ray November. How do you read? Over." <p> On board STS-9, Space Shuttle Columbia, was Dr Owen Garriott, W5LFL, now silent key. On the ground was Lance Collister, then WA1JXN, now W7GJ. <p> NASA published an Educational Brief for the Classroom that described Owen's set-up as a battery powered 5 Watt FM transceiver feeding a split-ring on a printed circuit board antenna that will be placed in the upper crew compartment window on the aft flight deck. Others reported that the radio was a Motorola handheld. Logging was done with a tape recorder velcroed to the transceiver. <p> Owen describes the antenna as a "well-designed, hand-held antenna, known as a 'cavity antenna', which could be velcroed to the window. It was about 24 inches in diameter and looked somewhat like a large aluminum (sic) cake pan" <p> There's an edited version of a similarly titled ARRL video called "Amateur Radio's Newest Frontier - ARRL documentary featuring Owen Garriot, W5LFL, on STS-9" showing the antenna as a copper tube, bent into a circle, mounted inside an open aluminium box that was hinged on the window to face outwards. <p> The NASA brief also described a range of frequencies and designated 145.55 MHz as the primary frequency over the United States. It included a whole section about synchronising clocks using WWV in Fort Collins, Colorado, odd and even minute transmission schedules and descriptions on how this should work. <p> Operating during time off, when the antenna was facing Earth, and being on air for about four hours during the mission, around 300 contacts were made across the globe. <p> Today we continue to experiment in space. The callsign N1SS is heard on-air regularly from the International Space Station, astronauts are often licensed radio amateurs, there's a permanent repeater on the ISS, we launch research spacecraft called nano-satellites or more popularly CubeSats for amateur radio at every opportunity. So far there's over 160 satellites and the adventure continues. <p> Speaking of experiments, albeit earthbound, the other day, my WSPR or Weak Signal Propagation Reporter beacon, using 10 milliwatts was heard 13,455 km away in Sweden, that's 1.3 Million kilometres per Watt. <p> What have you been up to in Amateur Radio lately? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The Contester In Me...
Foundations of Amateur Radio <p> So, I have a confession to make. I'm a contester. I'm not ashamed of this. While I'm in a confessing mood, I'll also mention that I've not participated in many contests in the past few years. This is not for the want of desire, but for the lack of motivation to fix things in my shack that are fundamentally broken. <p> On the weekend I participated in a local contest. I took part for six hours, got on-air and made noise, made about 30 contacts, had a ball. I wasn't playing to win, though I did use the opportunity to refresh and hone some of my rusty skills. <p> The next day I spent much too long converting my log into something that the contest organiser asked for. I also discovered that there was a duplicate entry in my log, not something which I'd expect with only so few contacts, but a reflection on the tool I was using to create my log. <p> I started writing down what I learnt from the experience, operating from my own shack, documenting what worked and what didn't. <p> I commented on several things relevant to me, but to give you a flavour, my operator position is terrible because I'm logging on my main computer and the radio is side-on when I'm facing the computer. The sun was shining directly into my eyes when facing the computer. Holding a microphone I didn't have hands-free, I still don't have an auto-keyer to save my voice, my foot pedal didn't work and my data interface was on loan to another amateur. <p> As I said, these things are specific to me. <p> Logging was worse. <p> It didn't quite bring me to tears, but as the contest went on, it became a problem. I started to write down what was wrong with the tool I was using with a view to submitting patches to fix it when I realised that it wasn't actually built as a contesting logging tool, so I stopped and instead started writing a new list, one that describes what a good contesting tool looks like. It builds on a decade of using different tools and participating in contests in all manner of different situations, from special portable event activations, through to the annual top-tier contests run from a purpose built contest station and everything in between. <p> So, what does the ideal contesting tool look like, for me? <p> It needs to be cross platform, as-in, I should be able to use it on whatever computer I have access to, my Linux workstation, a Macintosh Laptop, an Android phone or tablet and while I'm at it, Windows and iOS and I think it should be able to run on a Raspberry Pi. In other words, there shouldn't be a situation where you cannot run the tool because you have some random combination of operating system or CPU that the developer doesn't support. <p> It must be open source. By that I mean, the code should be available to the entire community. There are too many stories of great tools dying or being held hostage by individuals or small groups. The tool should continue to exist and be usable regardless of the participation of the original developer. Users should be able to fix things, add functionality, change themes, whatever. <p> You should be able to customise it because not every contest needs the same information. For example, the John Moyle Memorial Field Day, a contest run every year during March in Australia requires that VHF and UHF contacts record the maidenhead locator, a four or six character message that designates the location of the station. This is used to calculate distance between two stations and award points accordingly. Such a requirement isn't needed in most other contests. <p> Some contests are considered friendly contests, like the Remembrance Day contest in August. It's common to exchange your name, details about your station and have a chat. You'd be unpopular if you used that approach for the Oceania DX, the CQ World Wide or the CQ WPX contests. In other words, some fields are expected for some contests, but not for others. <p> The tool needs to be able to show if a contact is valid by whatever means the rules for a particular contest decide. It needs to automatically log the time, keep track of previous entries and know about the super check partial list to validate partial callsigns. <p> The user needs to be able to use either a keyboard or mouse, or both, to do all the common contesting data entry. No dependency on crazy keyboard shortcuts, no requirement to click the mouse to make an entry, in other words, the tool needs to be able to get out of the way of the contester. <p> I think it needs to have a plug-in system to accommodate different rules and it needs to be able to export data in whatever format the contest organiser expects. <p> You should be able to use it without needing to be connected to the internet during the contest, it should be easy to update and have the ability to keep a station log for all the contacts ever made. <p> It would be great if it could also import existing logs so you can start to consolidate older logs. <p> Having spent quite some time looking for such a tool and failing, I've come to the conclusion that there's only one thing for it, I'm going to have to write my own tool and it would be great if you could help by sharing your opinion on the matter. <p> At this point I'm looking for suggestions on what you think is needed for a great contesting tool. I realise that for some, pen and paper is sufficient, and I'm not trying to dissuade you from using that, I've used it myself on more than one occasion, rather, I'm asking if you can think of things that it should do out of the box, things that are basic functionality that you would like to see as part of the design. <p> You can find the project on my vk6flab GitHub page, comment on Reddit, or you can drop me an email, cq@vk6flab.com. <p> Look forward to hearing from you. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What's with a negative SNR?
Foundations of Amateur Radio <p> We describe the relationship between the power of a wanted signal and unwanted noise as the signal to noise ratio or SNR. It's often expressed in decibels or dB which makes it possible to represent really big and really small numbers side-by-side, rather than using lots of leading and trailing zeros. For example one million is the same as 60 on a dB scale and one millionth, or 0.000001 is -60. <p> One of the potentially more perplexing ideas in communication is the notion of a negative signal to noise ratio. Before I dig in how that works and how we can still communicate, I should point out that in general for communication to happen, there needs to be a way to distinguish unwanted noise from a desired signal and how that is achieved is where the magic happens. <p> Let's look at a negative SNR, let's say -20 dB. What that means is that the ratio between the wanted signal and the unwanted noise is equivalent to 0.01, said differently, the signal is 100 times weaker than the noise. In other words, all that a negative SNR means is that the ratio between signal and noise is a fraction, as-in, more than zero, but less than one. It's simpler to say the SNR is -30 dB than saying the noise is 1000 times stronger than the signal. <p> Numbers like this are not unusual. The Weak Signal Propagation Reporter or WSPR is often described as being able to work with an SNR of -29 dB, which indicates that the signal is about 800 times weaker than the noise. <p> To see how this works behind the scenes, let's start with the idea of bandwidth. <p> On a typical SSB amateur radio, voice takes up about 3000 Hz. For better readability, most radios filter out the lower and upper audio frequencies. For example, my Yaesu FT857d has a frequency response of 400 Hz to 2600 Hz for SSB, effectively keeping 2200 Hz of usable signal. <p> Another way to say this is that the bandwidth of my voice is about 2200 Hz, when I'm using single side band. That bandwidth is how much of the radio spectrum is used to transmit a signal. For comparison, a typical RTTY or radio teletype signal has a bandwidth of about 270 Hz. A typical Morse Code signal is about 100 Hz and a WSPR signal is about 6 Hz. <p> Before I continue, I should point out that the standard for measuring in amateur radio is 2500 Hz. <p> This is significant because when you're comparing wide and narrow signals to each other you'll end up with some interesting results like negative signal to noise ratios. This happens because you can filter out the unwanted noise before you even start to decode the signal. That means that the signal stays the same, but the average noise reduces in comparison to the 2500 Hz standard. <p> This adds up quickly. For a Morse Code signal, it means that turning on your 100 Hz filter, will feel like improving the signal to noise ratio by 14 dB, that's a 25 fold increase in your desired signal. <p> Similarly, filtering the WSPR signal before you start decoding will give you roughly a 26 dB improvement before you even start. <p> But there's more, since I started off with claiming that WSPR can operate with an SNR of -29 dB. I'll note that -29 dB is only one of the many figures quoted. I have described testing the WSPR decoder on my system and it finally failed at about -34 dB. Even with a 26 dB gain from filtering we're still deep into negative territory, so our signal is still much weaker than the noise. <p> There are several phenomena that affect the decoding of a signal. <p> To give you a sense, consider using a limited vocabulary, like say the phonetic alphabet, or a Morse character, the higher the chance of figuring out which letter you meant. This is why it's important that everyone uses the same alphabet and why there's a standard for it. To send a message, WSPR uses an alphabet of four characters, that is, four different tones or symbols. <p> Another is how long you send a symbol. A Morse dit sent at 6 words per minute or WPM lasts two tenths of a second, but sent at 25 WPM lasts less than 5 hundredth of a second This is why WSPR uses two minutes, actually 110.6 seconds, to send 162 bits of data, lasting just under one and a half seconds each. <p> If that's not enough, there's a processing gain. One of the fun things about signal processing is that when you combine two noise signals, they don't reinforce each other, but when you combine two actual signals, they do. Said in another way, signal adds coherently and noise adds incoherently. <p> To explain that, imagine that you have an unknown signal and you pretended that it said VK6FLAB. <p> If you combined the unknown signal with your first guess of VK6FLAB and you were right, the unknown signal would be reinforced by your guess. If it was wrong, it wouldn't. If your vocabulary is small, like say four symbols, you could try each in turn to see what was reinforced and what wasn't. <p> There's plenty more, things like adding error correction so you can detect any potentially incorrect words. Think of it as a human understanding Bravo when the person at the other end said Baker. <p> If you knew when to expect a signal, it would make it easier to decode, which is why a WSPR signal starts at one second into each even minute and each symbol contains information about when that signal was sent, which is why it's so important to set your computer clock accurately. <p> Another is to shuffle the bits in your message in such a way that specific types of noise don't obscure your entire message. For example, if you had two symbols side-by-side that when combined represented the power level of your message, a brief burst of noise could obliterate the power level, but if they were stored in different parts of your message, you'd have a better chance of decoding the power level. <p> I've only scratched the surface of this, but behind every seemingly simple WSPR message lies a whole host of signal processing magic that underlies much of the software defined radio world. <p> These same techniques and plenty more are used in Wi-Fi communications, in your mobile phone, across fibre-optic links and the high speed serial cable connected to your computer. <p> Who said that Amateur Radio stopped at the antenna connected to your radio? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Acronym not found ...
Foundations of Amateur Radio <p> Our community is full of TLAs, or three letter acronyms. Some of them more useful than others. For example, I can tell you thank you for the QSO, I'm going QRT, QSY to my QTH. Or, thanks for the chat, I'll just shut up and take my bat and ball and go home. <p> Acronyms arise every day and it came as no surprise to spot a new one in the wild the other day, SHF. It was in a serious forum, discussing antennas if I recall, so I didn't blink and looked it up. Super High Frequency. Okay, so, where's that? <p> I'm familiar with VHF and UHF and as radio amateurs we're often found somewhere on HF, that's Very High Frequency, Ultra High Frequency and High Frequency if you're curious. <p> Turns out that the ITU, the International Telecommunications Union has an official list, of course it does. The current ITU "Radio Regulations" is the 2020 edition. It's great bedtime reading. Volume one of four, Chapter one of ten, Article two of three, Section one of three, Provision 2.1 starts off with these words: "The radio spectrum shall be subdivided into nine frequency bands, which shall be designated by progressive whole numbers in accordance with the following table." <p> When you look at this table you'll discover it starts with band number four and ends with band number twelve, between them covering 3 kHz to 3000 GHz. In position ten you'll see the designation "SHF", covering 3 to 30 GHz, centrimetric waves. <p> A couple of things to note. <p> The list starts at band four. There are of course frequencies below 3 kHz. The list ends at twelve, but there are frequencies above 3000 GHz. You'll also note that I'm not saying 3 Terahertz, since the ITU regulations specify that you shall express frequencies up to 3000 GHz using "gigahertz". <p> Interestingly the same document has a provision for reporting interference where you can report using Terahertz frequencies, so I'm not sure how the ITU deals with such reports. <p> Another thing to note is that this table doesn't actually define what SHF means. It's nowhere in the radio regulations either, I looked. I'm not sure where the words Super High Frequency came from. There is an ITU online database for looking up acronyms and terms. That leads to a document called "Nomenclature of the frequency and wavelength bands used in telecommunications", which also doesn't use "Super High Frequency" anywhere. <p> That said, using the ITU band four, where its definition starts, the VLF band, or Very Low Frequency, followed by LF, Low Frequency, MF, Medium Frequency, the familiar HF or High Frequency, VHF, UHF, then SHF and beyond that, EHF, Extremely High Frequency and THF or Tremendously High Frequency, yes, Tremendously High. <p> There's a report called the "Technical and operational characteristics and applications of the point-to-point fixed service applications operating in the frequency band 275-450 GHz". It introduces the term "THF which stands for tremendously high frequency" but adds the disclaimer that "this terminology is used only within this Report." <p> Seems that there are plenty of documents on the ITU website using that same definition, so I'm guessing that the cat is out of the bag. THF by the way is defined as being for 300 to 3000 GHz frequencies. <p> By the way, the ITU TLA finder exposes that THF stands for Topology Hiding Function. Where's a good acronym when you need it? <p> Speaking of definitions, I came across the definition of a "taboo channel" which according to the ITU is "A channel which coincides with the frequency of the local oscillator in the single super heterodyne receiver which is tuned to an analogue channel." <p> Anyway, we still have a way to go. <p> Below band four, less than 3 kHz, we have ULF or Ultra Low Frequency, SLF, Super Low Frequency and ELF, Extremely Low Frequency, which is defined as band one, between 3 and 30 Hz. Below that, some have suggested TLF, or Tremendously Low Frequency which apparently goes between 1 and 3 Hz with a wavelength between 300,000 down to 100,000 km. Others have suggested that this is an internet meme, but so far it seems to me that it has just as much legitimacy as any of the other wordings, since it appears that the ITU explicitly excludes such definitions, even if internal documents introduce terms from time to time. <p> It did make me wonder, what comes after Tremendously High Frequencies, Red? <p> Turns out, yes, well, infra-red pretty much follows on from Tremendously High Frequencies. <p> If you think that's the end of it, think again. The IEEE, the Institute of Electrical and Electronics Engineers has its own definitions, of course it does. Unfortunately they decided that you need to pay for their standard. It was first issued in 1976 "to remove the confusion". There's an xkcd comic called "Standards", number 927 if you're looking. It goes like this: <p> Situation: There are 14 competing standards. 14?! Ridiculous! We need to develop one universal standard that covers everyone's use cases. Yeah! Soon: Situation: There are 15 competing standards. <p> Anyway, the IEEE designates that after UHF comes L or Long wave, followed by S, or Short wave, then comes C, the compromise between Short wave and X or cross or Exotic. Then there's Ku, Kurtz Under, K, Kurtz, and Ka or Kurtz above, Kurtz being the German word for Short. There's the V band and the W band which follows the V band. <p> Had enough yet? <p> NATO, the EU and the US define these using letters of the alphabet. <p> And broadcasters use Band Numbers which link up to nothing in particular. <p> I wonder if the measure of a society is just how many different ways can be used to describe the same thing. Perhaps we should have stopped at Hertz or Hz, which was established in 1930 by the International Electrotechnical Commission, as an expression of the number of times that a repeated event occurs per second, in honour of Heinrich Hertz. <p> One more three letter acronym, the International Electrotechnical Commission is better known as the IEC. <p> I wonder if the ITU is taking suggestions, ginormous, utterly, inordinately, awfully and humongously seem like perfect opportunities for future expansion. <p> I'm Onno VK6FLAB.
Listen: podcast - audio/mp3

Antenna Testing Day ...
Foundations of Amateur Radio <p> Last week I went outside. I know, it was a shock to me too. The purpose of this adventure was to test an antenna that has been sitting in my garage for nearly a year. Together with a friend we researched our options and at the end of the process the Hustler 6BTV was the answer to our question. Before the commercial interest police come out of the woodwork, I'll point out that I'm not providing a review, good or bad, of this antenna, it was the antenna I purchased and went to test. <p> Between the two of us we have three of these antennas. I have the idea to use one as a portable station antenna and another as my base station antenna. Glynn VK6PAW intends to use his as a base station antenna. <p> To set the scene. The antennas came in quite large boxes, just over six bananas long, or more than 180 cm. When they arrived I opened my boxes and checked their content, then sealed it all up and put the boxes on a shelf. Last week Glynn proposed that we set one up and see what we could learn from the experience. <p> You know that I love a good spreadsheet, so planning went into overdrive, well, I put together a list of the things we'd need, starting with the antenna and ending with sunscreen to protect my pasty skin from the fusion experiment in the sky. In between were things like an antenna analyser, spare batteries, tools, imperial, since apparently there are still parts of the world that haven't gone beyond barley measurements. I jest, they authorised the use of the metric system in 1866. My list also included a magnetic bowl to capture loose nuts and washers, you get the idea, anything you might need to test an antenna in the field. <p> Our setup was on a rural property where we had lovely shady trees and oodles of space to extend out a 25m radial mat. We tested many different set-ups. I won't go through them all, but to give you an idea of scale, in the time we were there, we recorded forty different antenna frequency scans. The 6BTV antenna is suitable for 80m, 40m, 30m, 20m, 15m and 10m. We tested with and without radials, raised and on the ground and several other installations. <p> We learnt several useful things. For starters, sitting on the ground with radials the antenna measurements line up pretty well with the specifications and with a suitable base mount to protect the plastic base the portable station antenna is usable out of the box. <p> Any variation on this will result in change, sometimes subtle, sometimes less so. For example, we came up with one installation where the SWR never dropped below 3:1. That's with the antenna on the ground without any radials in case you're wondering. <p> Other things we learnt were that manually scanning each band is painful. When we do this again we'll have to come up with a better way of measuring. The aim for my base antenna is to install it on my roof, bolted to a clamp on the side of my metal pergola. This means that we're going to have to do some serious tuning to make this work for us. It might turn out that we'll start with installing the antenna at Glynn's QTH first, but we haven't yet made that decision. <p> Other things I learnt are that I had actually put together the base clamp when I checked the boxes a year ago, so that was a bonus. The magnetic bowl saved our hides once when a spring washer fell into the lawn. The hose-clamps that come with the antenna require a spanner, but there are thumb screw variations of those that I'll likely use for my portable setup. <p> Other things we need to do is learn exactly how the traps work and how adjusting them affects things. In case you're unfamiliar with the concept of a trap, think of it as a radio signal switch that lets signals below a certain resonant frequency pass and blocks signals above that frequency. In other words, a 10m trap resonates just below 28 MHz. It lets frequencies below 28 MHz pass, but blocks those above it, essentially reducing the length of the antenna to the point where the trap is installed. <p> One test we did was to only use the base and the 10m trap. We discovered that this doesn't really work and that the metal above the trap, as-in the rest of the antenna, isn't just for show, even though it's on the blocked side of the 10m trap. <p> Given that I intend to use my base antenna as my main WSPR transmission point, I need to adjust things so the antenna works best on WSPR frequencies. I intend to use a tuner for when I want to work outside those frequencies. <p> One unexpected lesson was that the awning that Glynn attached to his vehicle was an absolutely essential item. I don't think I'll ever go portable again without one. Life changing would be an understatement. I'm investigating if I can fit one to my vehicle. <p> Having had some health issues over the past months I was anxious about going outside and being somewhat active. I paced myself, protected my back, took regular breaks, sat down a lot, drank litres of water and slept like a baby that night. No ill effects, very happy. <p> As a bonus, I even transferred our measuring data to a spreadsheet. <p> I can't wait to see the results of our next adventure. <p> Oh, we did connect a radio. Heard a beacon in Israel, heard a QSO in Italy, listened to WWV on 10 MHz and almost missed the bliss of not having to tune or switch when moving from band to band. <p> What have you been up to in the great outdoors? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Are all spiky antennas the same?
Foundations of Amateur Radio <p> The world is filled with antennas. You'll find them on towers, buildings, cars and on your next door neighbour's roof. They come in an astonishing variety, to the point where you might start thinking that antennas are a fashion accessory that vary with the season and if you start digging through the history books you'll come across designs that dial that variety up to eleven. <p> Possibly the most visible antenna today is the television antenna and when you start noticing them, the more variation you'll discover. <p> Their basic shape consists of a vertical pole, the mast, with a horizontal pole, the boom. Attached to the boom are various different shapes, or elements, that often vary in length according to some pattern. <p> The shape is designed to collect as much electromagnetic radiation from a particular direction, or in the case of a transmitter, focus as much energy as possible into one direction. This focus is called gain. The more focus, the more gain. <p> One of the oldest designs for this kind of antenna, still in use today, is the Yagi-Uda or Yagi antenna. It was invented in 1923 by Shintaro Uda at the Tohoku Imperial University in Japan and popularised to the English speaking world by his boss Hidetsugu Yagi who claimed to be the sole inventor in his Japanese patent application. He went on to file similar patents in Germany and the United States. <p> Gain for a Yagi varies depending on design. Generally more elements means more gain. Sometimes you'll see a Yagi with weird shorter elements along the boom. This is a design to make the antenna work across multiple frequencies. Another way that this can be achieved is by adding traps along an element. They look like a thick stubby tube at some distance along an element. You can have more than one of these to allow for more frequencies. These improvements allow for several Yagi antennas to share elements and boom space, essentially combining several independent antennas into one. <p> It can be tricky to discover in which direction a Yagi is pointing, but essentially the boom indicates the direction and the end with the shortest element is the front. <p> There's another type of antenna that to the casual observer looks similar. It's called a log periodic dipole array, LPDA or log periodic antenna. It was invented in 1952 by John Dunlavy whilst he was contracted to the United States Air Force. He wasn't credited because it was classified as "Secret", later changed to "Restricted". In 1958 Dwight Isbell built a log periodic antenna as an undergraduate student at the University of Illinois at Urbana-Champaign. He was part of a larger team that included Raymond DuHamel, John Dyson and Robert Carrell. Later Paul Mayes developed a variant that improved performance. <p> Before I dig in, I'll also note that this antenna caused all manner of legal issues that are still in force today. The so-called Blonder-Tongue Doctrine states that a patent holder isn't permitted to re-litigate the validity of a patent that has been held invalid previously. It was a result of the University attempting and ultimately failing to protect its patent for the widely copied antenna design. Reading about this is a fascinating discovery in how a single Judge can make a massive impact on law and society. <p> The log periodic antenna is designed in a way that to the uninitiated looks very similar to a Yagi antenna. It's based on the idea that you can design an antenna made up from independent dipoles that are spaced in such a way that they form an antenna where each dipole radiates to take advantage of its neighbours. Generally a log periodic antenna looks like a triangle. Often the elements are on two separate booms, alternating side-to-side, or you'll see a zig-zag structure that causes the antenna signal to alternate side-to-side. <p> One characteristic of an antenna is called bandwidth. It's a measure of how many frequencies it can operate on within the constraints of the antenna. The wider the bandwidth, the more frequencies you can use with the same antenna. <p> A Yagi antenna typically operates within about four percent of the design frequency. If you combine multiple Yagis by adding traps or different length elements, you'll end up with several frequencies, each with a similar range. <p> A log periodic antenna on the other hand is designed to be used across a large range of frequencies. In shortwave broadcasting there are log periodic antennas that operate between 6 and 26 MHz. In more common use today you'll find log periodic antennas used for higher frequencies. It's not unusual to find log periodic antennas that operate between 400 and 4000 MHz. <p> For even more confusion, you can share the boom of a log periodic antenna with a Yagi antenna as is popular in fringe television reception areas. <p> Some other things to note are that for a Yagi most of the elements are passive and only one is generally a driven element, in a log periodic antenna all elements are driven. For a Yagi antenna, more elements means more gain, whereas for a log periodic antenna it means more frequencies. <p> I'll also point out that there are experiments where the frequency range for Yagi antennas is being increased to more than twenty percent of the main frequency by varying the design. Much of this is achieved by using computer simulations to test many different virtual antennas until one promising design pops out. This optimisation technique can also be applied to log periodic antennas resulting in very interesting shapes that look nothing like the antennas you see on the roof today. <p> I've completely skipped over how these antennas are actually fed, as-in, how is the coax connected to the antenna. That's a whole different topic of conversation worthy of many hours of research and discussion. <p> Next time you look at a spiky antenna you should be able to discover if it's a Yagi or log periodic, or both and why. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Some Amateur Radio ABCs ...
Foundations of Amateur Radio <p> A is for Antenna, the eyes and ears of any amateur station. You'll spend eighty percent of your life attempting to get twenty percent improvement for any antenna you'll ever use. <p> B is for Balun, bringing together the balanced and unbalanced parts of your antenna system. <p> C is for Coax, the versatile conductor that snakes into your station, one roll at a time. <p> D is for Dipole, the standard against which all antennas are measured, simple to make, simple to use and often first in the many antenna experiments you'll embark on in your amateur journey. <p> E is for Electron, source of all things RF, the beginning, middle and end of electromagnetism, the reason you are an amateur. <p> F is for Frequency, the higher you go, the faster it happens. <p> G is for Gain, measured against a baseline, you'll throw increasing amounts of effort at getting more, one decibel at a time. <p> H is for Hertz, Heinrich to his mother, the first person to transmit and receive controlled radio waves in November of 1886 proving that James Clerk Maxwell's theory of electromagnetism was correct. <p> I is for Ionosphere, the complex and ever changing layers that surround Earth which led radio amateurs to discover HF propagation in 1923. <p> J is for JOTA, the Jamboree On The Air where radio amateurs, guides and scouts come together on the third full weekend of October to share global communications. <p> K is for Kerchunk, the sound caused by the local repeater that brings a smile to the operator and a grimace to the listener, created by pushing the talk button and not saying anything. <p> L is for Logging, the only way you'll ever remember who you spoke to and when and the perfect excuse for bragging to your friends after you managed to collect contacts all over the globe. <p> M is for Modulation, adding information to a radio signal by varying the amplitude, frequency, or phase. <p> N is for Net, a social excuse for getting on air and making noise with your friends. <p> O is for Oscillator, making repeating currents or voltages by non-mechanical means. <p> P is for Prefix, the beginning part of an amateur callsign that identifies your country or region of origin. <p> Q is for QRP, the best way to make just enough noise to make yourself heard, low power is the way to go! <p> R is for Resonance, the point where a circuit responds strongly to a particular frequency and less to others, used every time you tune a radio or an antenna or both. <p> S is for Shack, the space you call home, where you live your radio dream. The size of the corner of the kitchen table, the back-seat of your car or a purpose built structure with never enough space, no matter how much you try. <p> T is for Transceiver, a single box that contains both a transmitter and receiver that share a common circuit. <p> U is for UTC, Coordinated Universal Time, the only time zone that radio amateurs should use for any activity that goes beyond their suburb. <p> V is for VFO, the Variable Frequency Oscillator that provides radio amateurs with frequency agility, the means to listen anywhere, any-time. <p> W is for Waterfall, which displays radio signals across multiple frequencies at the same time. <p> X is for XIT, Transmit Incremental Tuning, changing your transmitter frequency whilst listening on the same frequency, helpful when you're trying to break through a DX pile-up. <p> Y is for Yagi, or Yagi-Uda antenna, the most popular directional antenna invented in 1926 by Shintaro Uda at the Tohoku Imperial University in Japan and popularised to the English speaking world by his boss Hidetsugu Yagi. <p> Z is for Zulu, the last word in the phonetic alphabet that every amateur should know and use. <p> 73 is for best regards. Saying goodbye is hard to do, this says so without fanfare and clears your station from the air. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Do you really know when the best time is to go on air?
Foundations of Amateur Radio <p> Getting on air and making noise is a phrase that you've likely heard me repeat often, actually, this will be the 24th time or so. It's an attempt at encouraging you to actually transmit and use the radio spectrum that is available to you. It's a nicer way of saying: Use it or lose it! <p> One of the more frustrating aspects of our hobby is finding other people to interact with. At the beginning of your hobby you have access to all these magic radio frequencies with no idea on how to use them. Often a new amateur will turn on their radio, call CQ a couple of times to see if there's anyone out there, hear nothing and give up. <p> As you get more experience you'll discover that radio frequencies change over time and that some work better at certain times of the day. This is reinforced by others who will talk to you about propagation, the solar cycle and how the ionosphere and its various so-called layers will change and what you can achieve throughout the day, the year and the long term cycle. <p> Armed with all this knowledge you are likely to get to a point where you make noise on a certain band depending on the time of day. <p> For example, experienced amateurs will avoid the 10m band at night because it's a so-called day-time band, in other words, their perception is that you cannot make contact on the 10m band after sunset and for the same reason, it's not suitable for early morning contacts. <p> What if we could test that perception and see if it's true or not? <p> Turns out that we have a perfect dataset to discover what actually happens. If I look at the 10m band WSPR or Weak Signal Propagation Reporter data for the past year, a year that had me using a beacon pretty much 24 hours a day, you'd expect that you could see just which times worked and which ones didn't. Turns out that regardless of time of day, my beacon was heard across every hour of the day. Of course the numbers aren't uniform across the day. The peak is at noon local time, the trough is at 5 am local time, 10% of reports are at noon, about 1.5% at 5 am. In other words, the worst time of day for my beacon to be reported is 5 am in the morning and it's not zero. <p> Interestingly the same isn't true for the signal to noise ratio, a measure of just how weak or strong a signal is in comparison to the local noise at the receiver. If you account for differences in transmitter power, meaning that a stronger transmitter is measured in the same way as a weaker one, the 10m band has the best signal to noise ratio at my location at 9 pm local time and the worst at 4 pm local time. <p> Given that I'm only using the 10m band with my beacon I also looked at the local OF78 grid square across all bands. It shows that reports are not directly related to when the average signal to noise is best. It seems to me that people are transmitting when they think it works best, not when it actually works best and I'll mention that the definition of "best" depends on each user. <p> Note that I haven't yet sat down to discover if there are automatic transmitter and receiver pairs that have been reporting 24/7 across a year on the same band to determine if there is more to learn about the relationship between how often something is reported and what the signal report was at the time. I can say that it's likely that your favourite band is more popular when others think it's popular, not when the conditions are better. <p> Consider for example that there are no local reports on the 12m band at 10am, but there are at 9am and 11am, so, was the band magically unusable the whole year at that time, or did people just not use it? The same is true for 160m. No reports at all before 5pm or after 3am, despite the bands around it having contacts throughout the day. <p> I will point out some things I've ignored. For example, what is a useful contact? Is it measured by distance, by quantity, by uniqueness? Is this choice the same for each band? Is it reasonable to compare a whole year, or should it be by some other time period, like month, season or lunar month? What is the signal to noise ratio for a band that's considered closed? <p> I'm mentioning this because each of those will directly affect what it looks like when you create a chart and it's likely to change what works best for you. <p> So, next time you get on air, try a band that shouldn't work according to your knowledge and see what happens. Perhaps you'll get lucky, make a contact and discover something unexpected. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The evolution of software in radio ...
Foundations of Amateur Radio <p> The amateur community is nothing if not entertaining. Look at any discussion about a mode like FT8 and you'll discover people who describe it as the dehumanising end of the hobby. In the same thread you'll find an amateur who's been licensed longer than I have been alive who welcomes it using words like revitalising, more active, and the like. <p> If you're not familiar, FT8 is one of many weak signal digital modes that gained popularity over the past years during the most recent solar minimum when long distance HF propagation was challenging. <p> That example discussion was about the visible end of a mode like FT8, but there's an often overlooked all but invisible aspect of these modes that is much more significant, namely the popularisation of signal processing in software. <p> In many ways amateur radio is more about receiving than transmitting. This might not be obvious, but what's the point of transmitting if you cannot receive? Using software to do the listening makes for an interesting evolution that might be hard to grasp if I start digging into the fundamental algorithms that make this happen, instead let me describe a process that is easier to explain. <p> Imagine that there's a piece of software that knows how to decode digital signals. As the user of that decoding software, or decoder, you send audio into one end and callsigns and grid-squares come out the other end. How it does this isn't important right now. <p> We measure the quality of this decoder by how many times it correctly does this, in other words, how many times a correct callsign and grid-square comes out. The decoder can be improved by changing the way that the decoding process works. If the number of correct callsign and grid-squares that come out increases, the quality of the decoder is improved. <p> Now imagine that the decoder spits out the callsign 7N5EC with the grid-square OF78. This particular combination emerged as a WSPR decode on the 10th of December 2022. It was reported by AA7NM as a 100 Watt signal, 14,882 km away on the 40m band. The signal report was -30 dB. <p> If you know where OF78 is, you'll immediately spot a potential problem, if not, I'll help you out, OF78 is located near Perth in Western Australia. It's unlikely that a transmitted callsign in that part of the world starts with anything other than VK6. Mind you, a weather balloon with an odd callsign could theoretically be overhead in that location, but I've not yet heard of a 100 Watt transmitter on 7 MHz that someone hung from a weather balloon. <p> Another problem is that 7N5EC is a callsign that appears to be Japanese. It starts with 7N which is part of the Japanese callsign block, but the next symbol is the number 5 and at least according to the research I was able to do is not actually a currently valid callsign. The prefix 7N4 is allocated to the Kanto region on Honshu island, the largest island in Japan. 7N5 doesn't seem to be valid as a prefix. Ironically, that callsign will now exist on the Internet as soon as this article is published, but that's a whole other problem. <p> Either way, the chances of the combination of the callsign 7N5EC with the grid-square OF78 is unlikely to be correct. It gets even less likely if you consider that the callsign was reported only once in fifteen years and over 500 million WSPR decodes, I checked. <p> That means that if you updated the software to ignore that particular decode, you'd have improved the decoder by removing an incorrect combination. You could keep doing this by checking callsigns against grid-squares and against allocated callsigns and you'd have made a higher quality decoder. <p> Before you start arguing that this isn't fair, it's exactly the same process as the super check partial list does for people operating in a contest. The idea being that if you only recognise known contesting callsigns, you've got a better chance of making contact. <p> Think of it as a way of filtering out potentially incorrect callsigns. It still leaves the operator having the option to ignore the suggested callsigns and listen to what's actually coming in. <p> I realise that this is not how you would realistically improve a digital signal processing decoder, but it's an example of how changing the software can change the quality of a decoder and that was the point of this example. In reality you'd attempt to discover how this decode happened and what caused it to be wrong. <p> If you want to consider a more signal centric example, consider a decoder that starts with a first attempt at making a decode. With a single decode, it can then remove that known signal from the original audio and start another decoding cycle. You can repeat this as many times as you want until you end up with gibberish. Essentially this is an example of how a modern decoder can improve its performance. <p> This is why signal processing in software is so powerful and important and why FT8 and the rest of the digital firmament are here to stay. I should point out for those wondering, FT8 and WSPR are examples of simple messages, but there's nothing stopping us from using digital messages like this to exchange little bits of audio, or video, or something else. It's how mobile phones work today and at some point amateur radio is going to extend the envelope and come up with the next thing, it always has. <p> So, FT8, it's changing amateur radio, but not because we're glued to a screen having our computer talk to another one, but because it represents digital signal processing in software and it's just the beginning. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Path loss and very small numbers ...
Foundations of Amateur Radio <p> Sometimes you learn mind boggling things about this hobby, often when you least expect it. Recently I discussed having my 20 mW WSPR or Weak Signal Propagation Reporter beacon heard on the other side of the planet, in Denmark, 13,612 km away. That in and of itself is pretty spectacular, but it gets better if you consider just how weak the signal was by the time it got there. <p> In radio communications there is a concept called path loss or path attenuation. Until recently I understood this to mean the things that impede a signal getting from transmitter to receiver. That includes coax and connector losses, refraction across the ionosphere, reflection off the surface of the planet and diffraction around objects. <p> It turns out there is another factor called "Free Space Path Loss" to consider. It's loosely defined as the loss of signal strength between two antennas. The name sort of implies that something happens to the signal in free space, which is odd if you know that in space, radio waves, regardless of frequency, travel without loss and will travel pretty much indefinitely. <p> So what's going on? <p> To get started, think about a dome lawn sprinkler, one of those little round discs that sits on the ground with the hose connected to the side. You turn on the tap and the water sprays in all directions. If you're really close to the sprinkler when the tap is turned on you'll get sopping wet almost immediately, since most of the water will hit you directly. This is particularly fun in the heat of summer on New Years Day in Australia, not so much in the middle of winter on the other side of the globe. <p> If you stand a couple of meters away, you'll still get wet, eventually, but it will take much longer, because most of the water isn't hitting you. If you stand even further away and assuming the water still gets that far, it will take even longer. <p> A small towel and a big towel will both take the same length of time to get wet if they're held at the same distance from the sprinkler, but if you wring them both out, you'll discover that the big towel captured much more water during the same time. <p> In radio communications we can combine these two ideas, the distance and the size of the receiver, to describe free space path loss. <p> The further away from the transmitter you are, the less signal is available to you to capture since much of the signal is not heading in your direction and the bigger your antenna, the more signal you receive. The bigger the antenna, the lower the frequency, which is why you'll discover that free space path loss is dependent on both distance and frequency. <p> To give you an idea of scale, the free space path loss for 28 MHz over 13000 km is about 144 dB. <p> While the name "Free Space Path Loss" implies loss of signal across the path in free space, the loss is not due to distance as such, rather it's caused by how much the signal is spread out in space. Similarly, there isn't more loss because the frequency is increased, it's that less signal is captured by the smaller size or aperture of the antenna required for a higher frequency. <p> So perhaps a better name might be Spherical and Aperture Loss, but then everyone would have to learn how to spell that, so "Free Space Path Loss" it is. <p> I'll point out that this is the minimum theoretical loss, in reality the loss is higher than this, since it also includes all the other parts of the path loss which are things that we can control, like coax and connector loss, and things we can improve by frequency selection, like ionospheric reflection and refraction which depend on solar conditions. <p> The one aspect of path loss that we have no control over is the "Free Space Path Loss", so perhaps that's why we don't talk about it very much. <p> I'll mention that in path loss calculations often antenna gain at the transmitter and receiver are used to reduce any path loss figures. If I have an antenna with 6 dB gain, then that reduces my overall path loss by 6 dB, which is why we spend so much time and effort figuring out what antenna to use when we get on air to make noise. <p> I mentioned that the free space path loss for my beacon between Australia and Denmark was about 144 dB. This means that my 20 milliwatt signal arrived in Denmark as a -131 dBm signal. That might not mean much, but that's the equivalent of about 80 attowatts. If you're not sure how big that is, 1 milliwatt is 1 quadrillion attowatts, a 1 with 15 zeros. Said another way, 1 watt is 1000 milliwatts, 1 milliwatt is 1000 microwatts. 1 microwatt is 1000 nanowatts, 1 nanowatt is 1000 picowatts, 1 picowatt is 1000 femtowatts, 1 femtowatt is 1000 attowatts. <p> It might come as a surprise, but these numbers are not unusual. Don't believe me? When your radio shows an S0 signal on HF, it is defined as -127 dBm, so we deal with tiny numbers like this all the time, we're just not quite aware of it on a daily basis. <p> Remember, my numbers are theoretical only, to give you an idea of scale. In reality everything in the path between the transmitter and receiver affects what ends up at the other end and might make the difference between hearing someone, or not. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What is the difference between handheld, mobile and a base radio?
Foundations of Amateur Radio <p> If you've ever been in the market for a new radio, and truth be told, who isn't, you'll find yourself faced with a bewildering array of options varying from obvious to obscure and everything in between. At the obvious end of the scale are things like price, bands and transmit power and at the other end are things like Narrow Spaced Dynamic Range, which you'll find explained by Rob NC0B on his sherweng.com website where he's been publishing receiver test data for many decades. <p> One of the more subtle options you'll need to consider are handheld, mobile or base radio. <p> This is harder than you might think, since radios are increasing in functionality every time you wake up and if you look long enough, you'll discover that they're getting smaller at the same rate. Once upon a time you could just look at the size of a radio and define it as belonging in one or other category, but that's no longer a useful distinction. For example, my PlutoSDR is a tiny device, fits in my pocket, but there's no way I'd consider it a handheld, or even a mobile radio. <p> You might think that a bigger box has more stuff inside, costs more and performs better. <p> For example, the Drake R-4C receiver and companion T-4XC transmitter require external power and were once rated by the ARRL as very good. In reality the Drake R-4C performed terribly in a CW contest, incidentally, that was what caused Rob to start testing radios in 1976. That receiver and transmitter manage to cover 80m, 40m, 20m, 15m and 10m and together weigh in at 14.3 kg. They're considered a base radio. <p> The Yaesu FT-817, runs on batteries, weighs in at just over a kilogram and can be carried with a shoulder strap. It comes as a single device and covers many more bands than the Drake transmitter and receiver do, it would be considered a mobile or even portable radio. Obviously it would be hard to jam a Drake into your car or strap it to your belt, but does that mean that you cannot use an FT-817 as the base radio in your shack? <p> In case you're curious, the slightly beefier brother to the FT-817, the mobile FT-857d, is sitting on my desk as my current base radio. Has been for years. <p> So why do manufacturers continue to make this distinction between handheld, mobile and base radio? One look at the nearest radio catalogue will tell you that it's not based on either performance or price, not even close. You can buy a handheld with more functionality for the same price as a mobile radio and that same is true when you compare a mobile radio to a base radio. <p> Radios vary in price from $20 to $20,000. A cynical person would suggest that pricing is based around extracting the most money from your pocket, but a more charitable explanation might be that physical size dictates things like the number of buttons you can fit on a radio, how many connectors can be accessed before the radio flies off the desk from the weight of the coax hanging off the box, how big is the display and other such limitations. <p> I'm not being glib when I use the word charitable, since much of modern transceiver design revolves around software which can pretty much fit in any box. Using external computers, neither buttons nor a display are needed, leaving external connectors, which if we're being really honest could all fit in a box that would fit in your pocket. <p> At this point you might wonder if handheld, mobile or base has any meaning at all. As I said, in most cases it doesn't. There's really only one place left where this matters, and that's when you have access to strictly limited space and power if you need to put the radio in your pocket or cram it into your car. <p> For your home shack, the distinction is unhelpful for most, if not all, amateurs. <p> Don't believe me? The Yaesu FT-710 currently ranks fourth on Rob's Sherwood Engineering Receiver Test Data List. It's a quarter the size of the top radio and it's sold as a "Base/Portable Transceiver". Yaesu calls it "Compact". It might not fit in the dashboard of my car, but it will fit on the folding table we use during field days. <p> That isn't an exception either. The Elecraft KX3 is the smallest radio on the first page of Rob's Receiver Test Data list. It fits in your pocket. <p> Before you start collecting statistics for each radio, I should point out that the more you know about this hobby, the harder this process becomes, so be careful. That said, if you have a massive list of anything to choose from, a new amateur radio, pet food, car, what to have for dinner, whatever, here's a process that will guarantee a result. <p> It works by eliminating one item at a time until you're left with your preference. <p> To start, grab the first two items on your list and pick the best one between the two. Ignore everything else, just those two items. You're going to fret about the definition of "best", but don't worry, since every time you do this, you'll have a different idea. All you're doing is saying, all things being equal, between these two options, which one do I prefer. No need to describe why, just pick one. In picking one, you've removed one option from the list. <p> Now, compare the winner to the next item on the list, again, ignore everything else and pick one and remove the other. Keep doing this until you run out of items. You'll end up with the single option that wins, for whatever reason, from the entire list. <p> Now, about that radio. All I need is the next paid project. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What should we be learning?
Foundations of Amateur Radio <p> It's an immersive effort to create an article every week, so much so, that I've only just discovered that I passed the 600 article mark some time ago. I'd open up a bottle of something celebratory if I thought it warranted the effort, but I'd rather talk about amateur radio and what I've learnt since becoming licensed in December of 2010. <p> This hobby, this community, the activity of amateur radio keeps surprising me in unexpected and exciting ways. I know that there is a part of the community that thinks of this as a dying hobby, but with every fibre in my being I know this to be wrong. We explore, test, build and learn at every opportunity. Put any two amateurs in contact with each other, either physically or over the air and you'll soon witness an exchange of ideas, of things that bring joy, hints of the next thing and the next. <p> The inspiration for my writing comes from all manner of places. For example, here's an opinion recently shared by someone on social media: <p> "Basic antenna modeling using software should be included in ham radio licensing exam syllabus if it's not currently." [sic] <p> As opinions go it's one of the tamer ones I've come across, but it's not unique in any sense of the word. I've heard it described bemoaning the missing knowledge of new digital modes or the need to upgrade my license, or the idea that the introductory license should come with a fixed expiry date. You might have heard similar ones, phrased along the lines of a missing attribute that new licensees should be required to learn or know about before they can call themselves amateurs. <p> It's also completely unhelpful. <p> Let me explain why. <p> I'll start with an analogy. When was the last time your driver's license expired because you didn't upgrade it due to new road rules, new vehicle types, new car accessories or speed limits? In case you're confused, the answer is: never. <p> Does amateur radio cause death and mayhem in the community? No. <p> Do cars? <p> So, in the scheme of things, even if amateur radio can be used to help save lives, it's not an activity that's generally considered life threatening. You could argue that radio amateurs could cause life threatening interference, and technically they can. So can any user of any piece of radio equipment, CB radio, mobile phone, Wi-Fi, you name it. Even a half asleep electronics student in their first year of high-school could do this. The skill isn't specific to radio amateurs. <p> So, what is this about, the requirement for antenna modelling, or some other missing skill, and why does our community keep getting flooded with such, frankly, nonsense? <p> In my opinion, it's the same phenomenon that laments the loss of Morse code, the fact that we lost the 11m band, that we're playing with FT8 instead of AM, that we prefer integrated circuits to valves. The world is a flowing feast and amateur radio is along for the ride. Stand still and the world moves on. <p> Should amateur radio licensing change? <p> Absolutely! <p> It should move with the times. It should lower the barrier to entry at every opportunity. It should explore the possible, not the requirements of a select group of people who decry the dumbing down of the hobby and want to pre-load every license exam with things that are absolutely irrelevant to the turning on of a radio and making noise. <p> Will amateurs benefit from knowing that antenna modelling software exists? Sure they will. Just like they'll benefit from knowing about valves and Morse code. That doesn't mean that they should be part of the exam process. I want new amateurs, no, all amateurs to be curious, to ask, to discover, to explore and to want to know stuff, not because it's a requirement to get a license, but because it's beneficial to their amateur journey. <p> Every week I come up with a different way to look at our hobby because this hobby is so divers. I've used the phrase a 1000 hobbies in one. So far I've just scratched the surface, some 600 weeks in. We'll see where we're at when I've held my license for another decade or so. <p> So, have at it. What is missing from the current exam and why should it be included? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Where does propagation data come from?
Foundations of Amateur Radio <p> One of the many questions that new amateurs ask is, "When should I get on-air, and on what band?" The often-heard reply is just to get on-air and make some noise. As time goes by, the importance of this seems to fade in favour of using HF prediction tools. Some amateurs never venture beyond that point, relying almost exclusively on technology to determine if they should turn on their radio or not. <p> If you search the internet for "current HF conditions", you'll end up with dozens of sites boldly claiming to provide precisely that information, some even using the label "Real-Time". You'll find instructions from countless self-proclaimed "experts" on how to read propagation conditions from their favourite site. There's even widgets that you can install on your website displaying propagation data per amateur band with helpful labels like "Band Closed" or showing conditions as "Poor", "Fair" or "Good". Some of these widgets even include an embedded time-stamp to prove just how "current" the information is. <p> If that's how you decide to activate your amateur station, like I once did, I have some questions. <p> Where is this information coming from, is it accurate, and when was it last updated? <p> To give you an idea of just how complex this question is, consider visiting two popular websites, solarham.net from Canada and spaceweatherlive.com from Belgium. On their home-pages, you'll find all manner of numbers, charts, photos, events, notifications, alerts, and warnings, each related in some way to HF propagation and the condition of the Sun. <p> Sounds great, excellent resources, job done. <p> Well, no. <p> Let's start simple. Location. <p> Leaving aside where the site's owner is or where the servers are, both potential sources of confusion, consider where you are and where the remote station is that you're trying to contact. Now compare that with the propagation data location. Do you know where the measurements came from and if they're relevant to you? <p> What about data currency? <p> For example, if you can see the Sun, you can count the number of sunspots since that data comes from physically looking at the Sun. Mind you, can someone count the number of sunspots at night? It's not a trick question. The Sun isn't overhead for everyone all the time, and the data from any particular observer will be out of date at night. When was the count updated? Is it still actually current, let alone real-time? Obviously, not everyone uses the same data source either. <p> In case you're wondering, why are we counting by eye in the space age? It turns out that, since Galileo more than 400 years ago, it's the most long-term, reliable way to keep data consistent between observers and instruments, both of which often last only one or a few solar cycles, and it's also cheap! <p> What about equipment changes and failures in data gathering? <p> Geomagnetic activity isn't global; it's measured using a device called a flux-gate magnetometer. Measurements from specific instruments scattered around the globe are combined into the planetary, or Kp index. You'll discover that locations used change over time, and when instruments are down, the numbers are estimated, but you won't see that unless you actually find and explore the source data. <p> It's not just solarham.net and spaceweatherlive.com; it's pretty much every single site that shows any form of HF propagation or space weather information. Even sites based in a specific country, like the Australian Space Weather Service, have many instruments scattered around Australia. If you happen to be near an actual instrument, where "near" is anything less than 500 km away, how do you know if that instrument was actually online when a measurement was made? <p> Even if the instrument near you is working, is the data relevant to the receiving station on the other side of the planet? <p> If you look closely at the sites giving out current HF conditions, you'll discover that most of these don't even tell you where the data comes from, let alone if any of it was estimated to come up with their current reported values or recommendations. <p> If you start searching for historical information, this problem gets bigger. You'll find many sites that claim to have data, but are invariably underfunded, are rife with broken links, out-of-date servers, and moved, deleted, and abandoned pages. If you unearth a dataset, you'll discover that everyone uses a different standard to record their measurements. <p> How do you even know if combined measurements are coming from the right column? Think I'm kidding? There are documents with warnings about different formats, calculations, and dates on which these changed. Aggregating this data is challenging, at best. <p> So, is there a better way? <p> Yup. You're not going to like it. "Get on-air and make noise!" <p> I can hear you groaning from here. It's not all bad. You can run your own beacon to see the conditions at your location. It's what started me down the path of installing a WSPR, or Weak Signal Propagation Reporter, beacon and leaving it running 24/7. Currently, I'm focused on very weak, 10 mW signals. So far, it's been reported 3,685 km away. <p> If you visit the VOACAP or Voice of America Coverage Analysis Program website, you'll find a visualisation of how FT8 propagation worked between ITU zones between 2017 and 2019. It's not current, but it's an excellent way to see how propagation data can be derived from actual contacts. <p> What we really need are more beacon transmitters and online receivers. <p> I'm Onno VK6FLAB.
Listen: podcast - audio/mp3

What's the weakest signal that WSPR can decode?
Foundations of Amateur Radio <p> In 2016, Daniel EA4GPZ, documented how to discover the weakest signal that could be decoded using several weak signal modes, including WSPR, or Weak Signal Propagation Reporter. This is an interesting question because as you might recall, I've been experimenting with very weak signals coming from my shack. To date, my 20 milliwatts has been heard over 13 thousand kilometres away. <p> When you tune to a weak station you'll often hear both the station or desired signal as well as interference or background noise. The stronger the signal, the less noise you perceive. The weaker the signal, the more noise. You can express the relationship between the power of these two, the signal and the noise, as a ratio. If the power levels are the same, the so-called signal to noise ratio or SNR is 1:1. A higher ratio, like 2:1, indicates that the power of the signal is higher than the noise and a lower ratio, like 1:2 indicates that the signal is lower than the noise. <p> If you express this ratio in decibels, you'll end up with positive numbers where the signal is stronger than the noise and negative numbers where the signal is weaker than the noise and zero when they're the same. If I tell you that the signal report for my WSPR decode from Denmark was -28 dB, it means that the noise was much stronger than the signal. <p> For today I'm going to leave alone just how WSPR can report a negative signal to noise ratio and still successfully decode the signal, even though the signal appears to be buried in the noise. <p> That said, in this experiment, we're trying to learn something else. Using the technique detailed by Daniel, we test using different, known, signal to noise ratios to discover at what point the WSPR decoding process breaks down. This might help me understand if I can reduce my beacon output power even further and still anticipate a good chance of being decoded successfully. <p> To conduct his experiment, Daniel used the then current version of WSJT-X, version 1.7.0-rc1 and I'm using the current version today, 2.6.0-rc5 to repeat those tests. You might ask why I'm not taking Daniel's word for it and just using his findings. The process to decode a WSPR signal is all software and can be improved with better methodologies and algorithms. It's not unreasonable to think that in the years since Daniel's experiments things have changed, hopefully improved. <p> So, how does this work? <p> If you generate and attempt to decode one hundred different files, you can use the number of times that you count your callsign in the decode list as a percentage of success. If all of your files decode properly, the decode percentage is 100%. If only half of them are decoded successfully, it's 50% and so-on. <p> Similarly, if a different callsign, locator or signal power is decoded, you can count those as a percentage of false decodes. This is important because noise coming from the ionosphere can corrupt any signal. I should point out that because we know in advance what the decoded signal should be, since we created the message, we can actually count the ones that don't match what we sent. In the real world it's very hard, if not impossible, to do this, unless each transmitter also starts recording their efforts so data cleaning can be done after the fact. <p> A false decode happens when the software decodes a message and the result is not what was sent. Due to the way that WSPR works, this is not a case of a single character error and as a result the whole message is corrupt, wrong callsign, wrong grid square and wrong power level. <p> Just how prevalent this issue is, has to my knowledge so far not been discussed. Over the past year I've been working with the entire WSPR data set, nearly 5 billion reports, and mapping the data to explore just what's going on behind the scenes. Based on the raw data every single grid square on the planet has been activated. Of course this is not really the case, since there's plenty of parts on Earth where we haven't yet turned on a WSPR beacon. <p> Back to our experiment. <p> Two tools are used, "wsprsim" to generate an audio file and "wsprd" to decode it. Both come with WSJT-X and when you build the application from source, you get them as part of the process. The generator takes several parameters, one of which is the desired signal to noise ratio. If you ask it for a signal to noise ratio of -20 dB, wsprsim will generate the appropriate noise and the desired signal, combine them and build an audio file. You can then use wsprd to decode that file. If you repeat this many times, you end up with some data. <p> How many times? <p> Well, I probably went a little overboard. I generated a set for each SNR reading between 0 and minus 50 dB in 0.01 dB increments and then generated one hundred for each of those. At the point where the process broke down I doubled the resolution further to get a better idea of what was going on. About three quarters of a million tests. It took a while. <p> What did I learn from this? <p> First of all, false decodes happen at every signal level. I saw the first false decode at a signal to noise ratio of -0.07 dB. This is significant because it means that even at excellent signal levels there is a percentage of incorrect reports which explains why I'm seeing that result in real world data. When you start playing with really big numbers, even if the error rate is low, with enough data, it starts to matter. In my tests I saw an error rate of 0.03%. This means that there's at least 1.5 million false decodes in the current WSPR data set, likely more because wsprsim cannot emulate the real world of ionospheric and local noise. <p> On the flip-side, I also saw an overall success rate of nearly 94%. At -29 dB things start to change. Until then the decode is 100% successful, then it starts to decline to 0 at about -34 dB. Comparing Daniel's results directly, he saw 34% success at -30 dB, I'm seeing 95% at that same noise level. At -31 dB Daniel saw 6%, I'm seeing 75%. I don't see 34% until we get down to -31.6 dB and 6% at -32.4 dB. This indicates that the software has improved over the years. <p> It also means that with a signal report of -28 dB from Denmark, I've got a few dB to play with. I've now reduced my output power by another 3 dB, making it 10 mW. Point your antennas at VK6 and see what you can hear on 10m. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

One Volt ...
Foundations of Amateur Radio <p> Have you ever asked yourself a question that turned out to be a rabbit hole so deep you could spend a lifetime exploring and likely never come out the other end? <p> I did. Yesterday. <p> What's a Volt? <p> This came about when I started exploring how to measure the power output of my WSPR or Weak Signal Propagation Reporter beacon. According to the specifications the output level is 23 dBm or 200 milliwatts. <p> If you read the fine print, you'll discover that the power output actually varies a little depending on which band you're on, for my specific transmitter it says that the output on the 10m band is 22 dBm, or 158 mW. <p> That comes with a disclaimer, that there can be some variation on individual transmitters of about 1 dB. So, on 10m, my output could vary between 21 and 23 dBm, or between 125 and 200 mW. With my attenuator connected, the output could be between 12 and 20 mW, and that's assuming that my attenuator is exactly 10 dB, it's not. <p> Measuring anything means to compare it against something else. To give you a physical example. If you look at a tape measure, the distance between the marks is determined in the factory. The machine that prints the lines is configured to make the lines just so. In the factory there will be a specific master tool that determines how far apart the lines are in that factory. That tool is called "the standard". The process of lining up the standard with the machine making the lines is called "calibration". <p> If you build a house on your own with just that tape measure, everything should work out fine, but if you have a mate help you and they bring their own tape measure, from a different factory, their lines might not quite match yours and the fun begins. <p> If you don't believe me, as I've said previously, pull out all the tape measures and rulers around your house and see just how much variation there is. <p> In my house, well, my CNC, there's a standard that came with my micrometer kit. It specifies physically how long 25mm is. I also have a 50mm and a 75mm standard. When I compare the 75mm with the 50mm and 25mm together, they're the same within one hundredth of a millimetre. It's likely that it's better than that, but I'm still learning how to hold a micrometer and not have it overheat and stretch while I'm measuring. Yes, temperature changes the size of things. <p> The point is, in my CNC world, my current standard sits in my micrometer box. At some time in the future I might want to improve on that, but for now it's fine. <p> The standard that I have was at some point calibrated against another standard. That standard was in turn calibrated against another standard and so-on. Eventually you end up with an SI unit of 1 meter as defined by the International System of Units. In case you're wondering, it's defined as the length of the path travelled by light in vacuum during the time interval of one second. One second is defined in terms of the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom. I know right, runs right off the tongue. I can't help myself, that frequency is 9,192,631,770 Hz. <p> Oh, this system is also subject to change. In 2019 four of the seven SI base units were redefined in terms of natural physical constants, rather than relying on a human artefact like the standard kilogram. This is an ongoing process. For example, in 1960, the meter was redefined as a certain number of wavelengths instead of a physical bar in a vault in Paris and there was also not just one bar, there were 30. National Prototype Metre Bar no. 27 made in 1889 was given to the United States and served as the standard for defining all units of lengths in the US between 1893 and 1960 - yes, perhaps surprisingly, the USA is metric, really. One inch used to be defined as "three grains of barley, dry and round, placed end to end lengthwise" but since 1959 is defined as exactly 2.54 centimetres or 0.0254 meters. <p> Back to power output on my beacon transmitter. Assuming for a moment that I had an actual tool available to measure this, I'd still be comparing my tool against another standard. <p> Let's imagine that I could measure the power output of my beacon with an oscilloscope. When the oscilloscope says 1 Volt per division. How do I know that it really is? If you start reading the calibration steps, you'll discover that they state that you need to connect your scope to a reference, another word for standard, and that's if you're lucky. Some documents just wave their hands in the air and say something like "push the auto calibrate button". <p> The Volt is defined as the electric potential between two points of a conducting wire when an electric current of one Ampere dissipates one Watt of power between those points. The Ampere definition involves counting elementary charges moving in a second. It's in the order of a 10 with 19 zeros. Not to mention that there's also a definition of how much an elementary charge is. You get the point, this is a rabbit hole. <p> So, now let's pretend that I have a calibrated oscilloscope. Let's say that our oscilloscope is calibrated within 1 dB. Cool. So I plug in my beacon and measure, what? <p> I'll end up with a reading, that's plus or minus 1 dB of "reality". In my case, perhaps I read 22.5 dBm. That means that it could be as low as 21.5 dBm or as high as 23.5 dBm, or between 141 and 224 mW. So, it's within specifications, great, but I don't actually know what the actual output power is. <p> Another way to look at this is to use a measurement to determine if the power is within specification or not. I'm guessing that Harry already did that test before he put my beacon in the box and shipped it to me. <p> Long story short, I'm no closer to knowing just how much power is coming out of my beacon, but I'm still working on finding a friend with a calibrated tool that might give me something a little more precise than fail or pass. <p> You know that there's a saying about turtles all the way down? I think it's rabbits myself. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Which way did it go?
Foundations of Amateur Radio <p> Propagation, the art of getting a radio signal from one side of the globe to the other, is a funny thing. As you might know, I've been experimenting with WSPR or Weak Signal Propagation Reporter and for about a year running a beacon on 10m. Out of the box my beacon uses 200 mW to make itself heard. I couldn't leave well enough alone and I reduced the output power. Currently a 10 dB attenuator is connected to the beacon, reducing output to a notional 20 mW. I say notional, since I haven't actually measured it, yet. <p> With so little power going out to my vertical antenna, a homebrew 40m helical whip, built by Walter VK6BCP (SK), and tuned to 10m with an SG-237, it's interesting to discover what's possible. <p> Last night my signal was heard in Denmark. Picked up by Jorgen OZ7IT, 13,612 km away. That report broke another personal best for me, achieving 680,600 kilometres per Watt. I was stoked! <p> I shared a screen-shot of my report with friends. One friend, Allen VK6XL, asked a very interesting question. "What makes you think it was short path?" <p> Before I go into exploring that question, I need to explain. If I was to fly from Perth to Sydney, the popular way to travel is across the Australian Bight, over Truro, north of Adelaide, clip the northern tip of Victoria, over the Blue Mountains to Sydney. The distance is about 3,284 km. This route is known as the great circle route, more specifically, the short great circle route. <p> It's not the only way to travel. <p> Instead of heading East out of Perth, if I head West, I'd fly out over the Indian Ocean, Africa, the Atlantic Ocean, the Americas, the Pacific Ocean and finally arrive at Sydney. That journey would also follow a great circle route, the long great circle route. It's about 37,000 km long. You might notice that I wasn't very specific with either the path or distance. There's a reason for that. None of the tools I've found actually provide that information, other than to point out that the entire circumference of the planet is about 40,000 km and that it's not uniform since Earth isn't a perfect sphere. <p> You might be asking yourself at this point why I'm spending so much energy worrying about taking the long way around and how that relates to my 20 mW WSPR beacon. <p> In amateur radio we refer to these two travel directions as the short-path and the long-path. <p> Radio signals travel along the curvature of Earth bouncing between the Ionosphere and the surface. How that works exactly is a whole different topic, but for the moment it's fine to imagine a radio signal skipping like a stone on water. As a stone skips a couple of things happen. If the angle at which it hits the water is just right, it will continue on its journey, get the angle wrong and you hear "plop". Every skip is slightly lower than the previous because the stone is losing a little bit of energy. Every time the stone touches the water it creates a splash that ripples out in a circle from the place where the rock hit. These ripples also get weaker as they increase in diameter. Consider what happens if you skip a rock across concrete or sand instead of water and if you really want to geek out, there's also wind resistance on the rock. <p> A complex equivalent dance affects a radio signal when it propagates between two stations. For success, enough radio energy needs to reach the receiver for it to be decoded. For our signal to make it to the other side of the globe it must bounce between the Ionosphere and Earth's surface. Every bounce gets it closer to the destination. Each time it loses a little bit of energy. This loss happens at the Ionosphere, at the surface and in between through the atmosphere. <p> To give you a sense of scale, my signal report from Jorgen in Denmark was -28 dB. It started here in Perth as 13 dB, so we lost 41 dB along the way. We're talking microwatts here. I'll note that I'm avoiding how this is exactly calculated, mainly because I'm still attempting to understand how a WSPR signal report actually works since it's based on a 2,5 kHz audio signal. <p> As I said, enough energy needs to make it to the receiver for any of this to work. <p> There's an assumption that less distance means less energy loss. It's logical. A shorter distance requires less hops and as each hop represents a specific loss, less hops means less loss. <p> But is that really true? <p> There's nothing stopping my beacon signal from taking a different route. Instead of travelling the short-path, it can just as easily head out in the opposite direction. Theoretically at least, my vertical antenna radiates equally in all directions. The long-path is mostly across water between Perth and Denmark. What if hops across the ocean were different than hops across a landmass? Turns out that they are in several ways. For example, there's less energy loss in a refraction across the ocean, how much less exactly is still being hotly debated. Much of the data is empirical at the moment. <p> It gets better. <p> What if I told you that the report was near to sunset? At that time there's a so-called grey line phenomenon related to how the sun stops exciting the Ionosphere and how different layers of the Ionosphere start merging. As a result the angles of refraction across the Ionosphere change and longer hops are possible. <p> What if the long-path took less energy to get to Denmark than the short-path did? <p> Would Jorgen's decoder care? <p> If that's the case, my signal didn't travel 13,612 km, it travelled twice that and I'd have well and truly cracked a million kilometres per Watt. <p> So, is there a way we could know for sure? <p> Well, yes and no. <p> For starters we'd need beacons that transmit at a very precise time. Then we'd need synchronised receivers to decode the signal. A signal travels 3,000 km in a millisecond, so we're going to need something more precise than the timing set by NTP or the Network Time Protocol used by your home computer. If we used GPS locked transmitters and receivers we'd be working in the order of 50 nanoseconds and be in the range of 15m accuracy. <p> That would allow us to calculate the physical distance a signal travelled, but that's not the whole story. <p> What happens if your signal travels all the way around the globe, or if some of it reflects back, so called back scatter, like the ripples from a stone coming back towards you, and that signal travelling back past you to the receiver? There's endless variation, since the planet isn't round with a flat surface nor is the Ionosphere. <p> So, do we know if my report was a long-path or a short-path? Not really. Based on the time of day, there's a good chance that it was a long-path report, but only if we actually measure the delay between send and receive will we have data to make a better assurance than "possibly" or "probably". <p> As I started, propagation is an art. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Morse is dead ... long live Morse!
Foundations of Amateur Radio <p> One of the oldest means of electronic messaging is Morse code. Developed by Alfred Vail and Samuel Morse and sent for the first time on the 24th of May 1844, Morse code changed the way we communicate. <p> For nearly a century it was required to become a licensed radio amateur until in 2003, the International Telecommunications Union or ITU left it to the discretion of individual countries to decide if a budding amateur needed to demonstrate their ability to send and receive in Morse. With that decision many thought that the end of Morse code was only a matter of time. <p> They were wrong. <p> Turns out that use and progress of Morse code continues at a surprising rate. Searching for scholarly articles on the subject, you'll discover that it's used, for communication by quadriplegics, for information exchange between IoT or Internet of Things devices, as a way to secure information combining DNA and Morse code, as a method for gesture recognition, as a research tool for psychologists interested in learning methodologies, for training neural nets, for REM sleep research and plenty more. <p> Learning the code is an activity that sparks joy or dread, depending on whom you ask. For me it's been a decade of anticipation with little to show for it. <p> How to learn is a question that prompts as many answers as there are people within earshot and most of those disagree with each other. If you do ask, you'll discover that there are dozens of websites that offer to teach you, podcasts and audio files, bits of paper, buzzers, software and video, images and cheat sheets, the list is endless. You'll also discover two terms, Koch and Farnsworth. Both are intended means of learning. You'll find proponents of both methods wherever you look. You'll also hear from people who learnt the Army way, whatever that means, there's people who were taught not to send before they could properly receive, those who were taught the opposite and everything in between. <p> There's discussion on the topic, heated even, but very little in the way of actual hard data. There's some research. In 1990 the Keller Method from World War 2 was explored. The method involves playing a Morse letter, followed by a gap where the student is expected to write the letter, followed by a voice prompt of the letter. Interesting, were it not for the fact that it looked at nine students and only at their ability to master the alphabet. <p> In 1960, 310 airmen were subjected to 14 tests to determine their ability to learn Morse. No idea what the research outcomes were, since the Journal of Applied Psychology doesn't appear to share their research unless you pay for it. <p> There are reports of actual science behind the Koch method of learning, but I wasn't able to find it, though it's repeated often. It's only with the introduction of computers that actually using this method of learning has become practicable and recently popular. <p> As you might know, I've been attempting to learn Morse code for a while now. I've tried many different things, including Farnsworth, Koch and others. I publish versions of my podcast as Morse code audio only. They're published every week and there are a few people who listen. <p> I also attempted to make stereo audio files with a computer generated voice in one ear and a Morse word in the other, I generated flash cards, I tried learning the code as dits and dahs, but in the end, nothing really worked for me. <p> About a month ago I came across a video on YouTube by Electronic Notes. It contained the Morse alphabet as audio and flashed the letter visually on the screen whilst the audio was playing. There's also a video with numbers and a combination of the two. <p> It gave me the idea for something entirely different to try and in preparing to talk about this, it turns out that there's even research to suggest that I might be on to something. I discovered that in 1994, sixty healthy people were tested to determine if learning Morse code in a rehabilitation setting was best achieved using visual, auditory or a combination of both. The research conclusion was that the combination works best. <p> My idea is a video that shows an individual word whilst Morse code for that word is heard. There's no dits and dahs on the screen, just the word, written in English, and the Morse code for the word. The speed is 25 Words Per Minute, or WPM, and it's played with a side-tone of 600 Hz. Each video is an entire podcast, lasts about 30 minutes, and plays at full speed. <p> I'm already beginning to notice that some words sound like a sound blob in much the same way as when I learnt a new language, so I'm hopeful that this will finally get me on my way. <p> It's early days and the video channel is an experiment, so please comment to share your thoughts on the experience. <p> Who knows, I might have introduced a new way to learn. <p> Now all we need is some research to compare it to other methods, Koch, Keller, Farnsworth and Onno, hi hi. <p> You'll be able to find this article on YouTube too, "Morse is dead ... long live Morse!" <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Attenuators, the missing link...
Foundations of Amateur Radio <p> Having been able to call myself an amateur for over a decade, it might come as a surprise to you that it wasn't until a couple of weeks ago that I thought about attenuators for the first time. They're a curious tool and once you come across them, you'll never be quite the same. <p> Before I dive in you should know that an amplifier is an active tool that makes things bigger and an attenuator is a passive tool that makes things smaller. To look at, attenuators are diminutive to say the least. The ones I have in my kit look like barrel connectors, a male and female connector and seemingly not much else, but looks can be deceiving and I'll mention that shape isn't universal. <p> The purpose of an attenuator is to reduce the power of an RF signal by a known amount, preferably without distortion or any impedance mismatches. When you go out hunting and gathering, your choice of connector is the first obvious selection, but soon after you'll be asked for a frequency range, an impedance, a power level and an attenuation level, so let's take a look. <p> I have some attenuators with N-type and SMA connectors. There's options for every connector under the sun, so consider what you're using with your gear and remember to think about your measuring equipment connectors as well. In my case my shack is pretty much SMA the whole way, but a friend had some broadcast N-type attenuators and I was unable to resist. <p> The next thing is impedance. In my case 50 Ohm, but there's options for other choices like 75 Ohm for TV based attenuators. <p> The purpose of an attenuator is to reduce power. It does so by converting power into heat and more power handling means more heat. Too much heat and the attenuator starts letting out the magic smoke, so consider how much power your RF source is generating. Putting out 5 Watts? Then make sure that you don't connect a 1 Watt attenuator to that radio. <p> Now for the attenuation level. It's described in dB or decibel. At first the numbers look bewildering, but pretty soon you'll be familiar with how it hangs together. A 3 dB attenuator will halve the signal, so a 10 Watt signal will be reduced to 5 Watts and a 200 mW signal will be reduced to 100 mW. <p> If you have a 6 dB attenuator, it will halve again, so 10 Watts becomes 2.5 Watts and 200 mW becomes 50 mW. <p> A 10 dB attenuator is a little more than 9 dB, so you could try something along the lines of a bit more than half again, but you don't need to. 10 dB attenuation is essentially moving the decimal point. A 10 Watt signal with 10 dB attenuation becomes 1 Watt. A 200 mW signal becomes 20 mW. <p> If you have a 20 dB attenuator, it moves the decimal point two places, 10 Watts becomes 0.1 of a Watt, or 100 mW and 200 mW with 20 dB attenuation becomes 2 mW. You can connect two attenuators together and combine their values by adding them together. For example, combining a 10 dB attenuator with a 3 dB attenuator makes for 13 dB attenuation which moves the decimal point and then halves that. <p> All that's fine and dandy, but what's the point? <p> Well, imagine that you want to measure the actual power output of your radio. If you were to pump the minimum power level of my Yaesu FT-857d into a NanoVNA you'd blow it up, but if you added say 20 dB attenuation, that 5 Watt would become 0.05 Watts or 50 mW which is half the power rating of the NanoVNA. If you're not confident that your radio is actually putting out 5 Watts, you could add 30 dB attenuation and have a safe margin at an expected output of 5 mW. <p> I mentioned that attenuators don't all look like an innocent barrel connector. That's because if you have to attenuate something with higher power levels, you'll need a way to dissipate heat, in much the same way as a dummy load has cooling fins, higher power attenuators can come with cooling fins too. <p> On the inside of this contraption is a simple circuit made from three or four resistors which combine to attenuate your signal. If you're inclined to build your own, there are plenty of online calculators to be found that show how to put an attenuator together. <p> One thing I've skipped over is the frequency range. Most of us are having fun with HF, VHF and UHF, generally below 1 GHz, so most attenuators will be fine, but if you are playing at higher frequencies you should take note of the frequency range specified for the attenuator. <p> While on the subject of frequency range. You can easily measure the actual performance of an attenuator using a NanoVNA. Connect Port 1 to Port 2 through your attenuator and using the magnitude trace you can see just how much attenuation it provides. Be sure to set the intended frequency range and calibrate without the attenuator before measuring. <p> Now that I know about attenuation, I cannot imagine a life without, but to be fair, I was in blissful ignorance for more than a decade, so this might not apply to you, yet, but one day perhaps you'll find yourself thinking about adding some attenuation to your tool kit. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How low can you go?
Foundations of Amateur Radio <p> It's common knowledge that power, as in output power, makes your signal heard in more places. If you've followed my adventures you'll also know that I'm a firm believer in low power or QRP operation. <p> It all started when I was told that my shiny new amateur license was rubbish because I was only allowed to use 10 Watts. Seemingly the whole community around me shared that opinion and slogans like "life's too short for QRP" are still commonly heard. <p> As a direct result of that sentiment I decided to explore and document just how much I could actually do with my so-called introductory license, the Australian Foundation License. I've now held it for over a decade and I'm still exploring and writing. <p> One of my first acts of rebellion was to lower my radio output power to its minimum setting of 5 Watts and half legal power was sufficient to prove my point. <p> Although I'm still regularly being encouraged to upgrade, my second act of defiance is to keep my Foundation License until I decide that I need more. I'll let you know if it ever happens. <p> One more well known so-called "fact" about our hobby is that if you use low power you'll really only get anywhere on the higher bands, 2m, 70cm and above. There's plenty of reports of amateurs using a low power handheld radio to talk to the International Space Station and my own satellite internet used 1 Watt to get to geostationary orbit. On HF on the other hand, 5 Watts is as low as you really want to go. Making contacts is a struggle and often frustrating, but when you do, bliss! <p> About a year ago I took delivery of a WSPR beacon. It's capable of transmitting on all my accessible HF bands using 200 mW. Given my antenna situation I've configured it to transmit on the 10m band, 24 hours a day, thunderstorms excepted. When making the purchase decision I had no insight into how my beacon would perform. 200 mW is stretching even my love of low power, but I hooked it up and turned it on and waited. <p> It came as quite a surprise that my beacon was heard over 15 thousand kilometres away, not once, not a couple of times, but regularly. When I came up with my November challenge to see if I could improve on that I made an almost throw away comment about reducing power to see if I could still make the distance. <p> A couple of weeks ago I hooked up a 6 dB attenuator to my beacon, reducing the power from 200 down to 50 mW. It came as quite a surprise that my signal made it to the same receiver in the Canary Islands. My kilometre per Watt calculation shot up, quadrupling my previous record. <p> Just imagine, 50 mW making its way over a third of the way around the globe, bouncing between the ionosphere and the planet, just like any other HF signal. At that point I realised I had learnt a few things. You don't need stupid power to make a distant contact on HF either. I started wondering just how little power was needed to get out of the shack. <p> Yesterday I hooked up a 10 dB attenuator and within ten hours my now 20 mW beacon broke my own kilometre per Watt record again and based on the signal to noise numbers from previous contacts, I see no reason for that record to stand for very long. Once that happens I've got plenty more attenuators to play with and I'm not afraid to use them. <p> Now I'm on the hunt for an attenuator that will reduce my main radio output from 5 Watts. I'm told I should aim for double the power rating, but I also have to consider how to connect my antenna coupler which needs 10 Watts to tune, but that's a project for another day <p> When was the last time that you used really low power? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The nature of learning things...
Foundations of Amateur Radio <p> Recently I discussed the concept of a VFO, a Variable Frequency Oscillator. It's an essential building block for our amateur radio community. In describing the idea behind it, while making an error in one of the CB radio frequencies, thanks to Ben VK6NCB for picking that up, I skirted around how a VFO actually works. <p> In reality the VFO is a collective term that describes a whole range of different methods to vary a frequency. Naturally I continued my exploration and discovered a whole range of documentation on the subject. I even started writing about how one common method, a Phase Locked Loop or PLL, works and how a VCO, a Voltage Controlled Oscillator, operates as part of that. I'll come back to those shortly. <p> In doing my reading, since, as is often the case, I use my weekly contribution to the world as a method to learn things. I'll investigate a topic and attempt to describe who came up with it, what it means, how it works and what its place is in the world, the who, where, why and what of it, if you like. I suspect that comes from my very first introduction to broadcast radio where that was one of the very first things I was taught, thirty years or so ago. <p> If you've followed along for the decade I've been at this you'll know that I also intersperse such learning with observations about the things that I'm interested in. This is such an observation, a meta view if you will. <p> I discovered somewhat to my chagrin that the ways that an essential component of our hobby, a system called a Phase Locked Loop, was described in such academic terms, complete with formulas and detailed circuits and even component lists, spread over pages and pages of verbiage, or explained in YouTube videos lasting an hour or more. Of course there were some little gems, ElectronicNotes on YouTube manages to cover the basics in little over six minutes, but that's a rare example. <p> It reminded me of a website that I've been using to fill in the gaps in my understanding of SDR or Software Defined Radio and Digital Signal Processing or DSP. The PySDR.org site is an online textbook written by Dr. Marc Lichtman. He says about his method: "Instead of burying ourselves in equations, an abundance of images and animations are used to help convey the concepts [...]" <p> My weekly efforts have always attempted to do exactly that and I found myself in a place where such a thing didn't appear to exist for the concepts behind the PLL and VCO. My obvious response to that would be to write the missing document and as I said, I have a first draft of it sitting on my computer. <p> There's only one problem. <p> I don't yet "grok" the concepts. If you're unfamiliar with what grokking is, it means to understand intuitively and emphatically. It also means that unless I can describe it in less than a single page of A4 paper I don't understand what I'm saying and you'll get bored waiting for me to make a point. <p> Here's my point. <p> How do you learn concepts? What is it that you do to discover new topics of interest and how do you progress through the various stages between discovery and grokking? <p> For me it's about puzzle pieces. It's always been puzzle pieces. Little nuggets of information, almost trivial on their own, but after a while you get to a point where you have enough of them that you can start joining them together to grasp a more complex concept. <p> Here's a puzzle piece I discovered today. <p> Impedance: The difference between an explosion in air and one under water is impedance. <p> It's little concepts like that which make me get out of bed and discover what's on the horizon next. I'm also learning about double and triple conversion superheterodyne radio which I believe has a one-on-one parallel application in Software Defined Radio and Digital Signal Processing. Once I figure out how to describe it to you, I'll let you know. <p> The point of all this is that learning things is as much about understanding as it is about explaining. <p> Feel free to point me at new and interesting basic concepts. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What's in a VFO?
Foundations of Amateur Radio <p> One of the many acronyms that define the world of amateur radio is VFO. It stands for Variable Frequency Oscillator. That doesn't explain much if you're not familiar with the purpose of it and just how special this aspect of amateur radio is. <p> Much of the world of radio beyond our hobby, like broadcast television, WiFi and Citizen Band or CB, to name a few, uses radio spectrum in a particular way. On a television you change channels to switch between stations. Similarly, a WiFi network uses specific channels to make your wireless network a reality and the same goes for CB, different channels to make yourself heard. <p> Looking specifically at CB for a moment, if you look at channel 8 for example, depending on which type of equipment you have, your radio might be using 27.055 MHz, or 476.575 MHz, or 476.6 MHz. Each of those frequencies can be described as CB channel 8. The first is on the 27 MHz or 11m band, the second is if you're using a 40 channel radio, which is now depreciated and the third is if you're using an 80 channel radio. <p> If you look at digital broadcast television, channel 8 is on 191.5 MHz. On WiFi, channel 8 is on 2.447 GHz or 5.040 GHz. <p> You get the point, depending on where you are as a user of radio spectrum, channel 8 might mean a whole host of different things and as I've described with CB radio, that might even change over time. <p> Harry Potter needed magic to reach Platform Nine and Three-Quarters at Kings Cross Station to get to school. In a channelised world, getting to an in-between frequency is not possible if you're using licensed equipment, unless you're a radio amateur, then you can use magic to get into the gaps. That magic is called the VFO. <p> You might recall that our radios use many different frequencies internally to be able to filter out specifically what signal you want to hear. Most of those frequencies are fixed, in fact in the vast majority of cases these are actually tuned and calibrated to work in a very specific way. <p> The one exception is the VFO, it's by nature variable. It's likely calibrated, but it's not fixed and that allows our community to tune our equipment to any frequency we desire. <p> The traditional user interface for this is a big knob on the front of your radio, colloquially referred to as the dial, as-in turn the dial to change frequency. <p> This allows us something quite rare in radio land. We can be frequency agile. It means that if there's interference at a specific frequency, we can tweak our VFO and slightly modify where our radio is tuned. You use this almost subconsciously when you're on HF trying to tune to a particular station. <p> In the world of software radio there's likely no knob. You type in a number and the variable frequency oscillator in the radio is tuned to another frequency and the output signal, or transmit signal if you're making noise on-air, changes to another frequency. <p> Digital modes like WSPR, which generally use a very specific frequency also vary that frequency but in a different way. You set your radio to the appropriate so-called dial frequency, let's say 28.1246 MHz on the 10m band and then the software alters the signal by up to 200 Hz to change within the available audio range of your radio, altering between a low of 1400 Hz and a high of 1600 Hz, making the actual WSPR frequency on 10m between 28.1260 and 28.1262 MHz. <p> I'm mentioning the WSPR example because while we're frequency agile in our hobby, we do use channels as well. There's a specific set of frequencies set aside, channels if you like, for WSPR, FT8 and other modes. We do the same on the 2m and 70cm bands where we have rules for where repeaters are allowed to be. <p> It means that we get the best of both worlds. We have the stability and institutional knowledge where repeaters or some modes go, but we also get to play in any spot we want. <p> For example, there's nothing stopping me and a friend setting our radio to some random frequency within our license allocation and outside pre-allocated space and run a WSPR transmitter there. Only the two of us will know about it, well at least at first, but it allows us to experiment away from any other users who might experience interference from our tests and exploration. <p> The VFO is what makes our hobby so very interesting and it's what makes it possible to do weird and wonderful experiments. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

My Virtual Workbench
Foundations of Amateur Radio <p> With the ever increasing pace of innovation, well, change, I'll leave alone if it's actual innovation instead of marketing, we see new software released at an almost alarming rate. <p> There is an urge to stay abreast of this process, to update, upgrade and try new solutions as soon as they are presented to you by well meaning friends and colleagues, not to mention online marketing, uh, reviews and other enticements that make you click the button to install something to avert the fear of missing out. <p> If you've done this for a number of years, actually, who am I kidding, a number of weeks, you'll discover that this comes at a cost. One that the corporate world has attempted to address by using terms like Standard Operating Environment, backups, administrator privileges and other such annoying things that prevent users from trying something new and breaking things. <p> At home and in the shack most of that is not a problem. No corporate IT division around to stop you, but soon you'll discover that something you installed caused you grief, encouraged your logging software to stop talking to your radio, prevented you radio from changing frequency, or blocked the latest digital mode from working as intended. <p> I live in that world too, but with the benefit of an IT background I decided nearly a decade and a half ago that enough was enough. I bit the bullet and bought myself a new computer. I vowed to install only one tool on that laptop, a virtualisation environment, also known as a hypervisor. It allows you to run a virtual computer inside a window. Given enough CPU power you can run multiple virtual computers in multiple windows inside your actual physical hardware. <p> This gives you flexibility. You can run a copy of your favourite operating system in a virtual environment, install the latest and greatest software on it and if it breaks, you delete it and start again. In my case I'm running my daily desktop environment where I'm currently writing this as a virtual Linux machine inside my physical computer which is also running several other virtual machines, including some network monitoring tools, a software defined radio development environment, my accounting software and plenty of other things. <p> Each virtual machine is nothing more than a folder on my physical computer and making a full backup is as simple as making a copy of that folder. Better still, if I want to try a new version of something on a machine that I'm already using, I can duplicate the folder, fire up the copy of the virtual machine, install the new software and test it. If it works, great, if not, throw it away and start again. <p> Changing physical computers is also simple. Buy a new computer. Install the hypervisor, copy the machine folders across and start working. <p> From a security perspective, it also means that I can install a random bit of software recommended by a friend without getting worried about it stealing any of my information, given that my private information isn't on the virtual machine on which I'm installing this unknown piece of software. <p> I also use this to compile new bits of code. If I come across a project on GitHub that I'd like to try, I can fire up a brand new machine and install all the prerequisites without running the risk of breaking something that I rely on. It also means that I can test with different operating systems, from macOS, any flavour of Linux, copies of Windows and play with virtual copies of Android or if I'm feeling frisky, BeOS. <p> There are other ways to achieve some of this. For example, you could get yourself a Raspberry Pi and half a dozen MicroSD cards. Install an operating system onto a card, boot the Pi, install your new application and if you like it, use it. If not, wipe the card, start again. You can have a dedicated WSPR beacon card, a contest logging card, whatever you need, all separate, all easy to backup and change as needed. <p> If that's not enough, some virtualisation environments allow you to emulate different microprocessors, so you could run ARM code on an x86 processor, or vice-versa. <p> If you want more, you can investigate containerisation. A tool that allows you to essentially create a mini virtual machine and run a new environment using a single command, so fast that you essentially don't need to wait for it to start-up, allowing you to mix and match environments as needed. <p> At this point you might ask why I'm even talking about this. What does this have to do with amateur radio? <p> Well, it's how I have my test bench set-up. Sure I have a soldering station, multimeters, a NanoVNA, an antenna analyser and all that kind of great stuff, but my radio world is mostly software and in that space all my tooling is pretty much virtual, put together in such a way that I can pick and choose precisely how I want to test something without killing something I rely on. <p> I'm telling you about it because in my experience much of the amateur community still relies on a desktop computer running Windows and I have to tell you, there is so much more out there for you to explore. <p> What does your virtual workbench look like? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

A plan for distributed SDR decoding
Foundations of Amateur Radio <p> Yesterday I finally discovered the missing piece of information that will allow me to create a project that I've, if not outright spoken about, at least hinted at. <p> In an ideal world by now I'd have built a proof concept and would be telling you that I've published a GitHub repository under my callsign for you to explore. If wishing made it so. Unfortunately, currently sitting at a keyboard for anything longer than ten minutes or so makes it nigh on impossible to stand up, so you'll have to make do with hand waving and gesticulation rather than actual code, but for now, that's all I have. Consider this a design specification if you're so inclined. <p> So, big idea. <p> Imagine that you have a device that can listen to radio frequencies. This device is connected to a network and it shares the data to any number of different listeners which might each do something different with the information. <p> If you were to do this in the way we watch YouTube or listen to streaming audio, each listener would get their own unique copy of the data. If you have ten listeners, you'd have ten streams crossing your network, even if everyone was enjoying the exact same video or audio at the exact same time. <p> Instead I want the data coming from the device to have only one stream on the network and for as many different listeners or clients to access it as required at the same time. <p> Let's get specific here for a moment. I'm talking about using a software defined radio, could be a $25 RTL dongle, could be any SDR, that is tuned to a part of the spectrum, let's say the entire 40m band, and sends that radio information digitally onto the network. This network could be your local network, or it could theoretically be the internet, for now, let's just put it out on our own network. <p> So, you have a copy of the entire 40m band streaming across your network. Great, now what? Well imagine that you want to decode RTTY on 7.040. You fire up your decoder, point it at the network stream and decode RTTY. <p> Then you want to decode a WSPR signal, at 7.0386. You fire up your WSPR decoder, point it at the network stream and decode WSPR. <p> Then you want to decode FT8 on 7.056, same deal, fire up your decoder, point it at the network stream and decode FT8. <p> Now you want to compare two different RTTY decoders. Fire them both up, point them both at the same stream, decode both, simultaneously. <p> Of course you could do this with CW signals, with SSB signals, with any decoder you have lying around, Olivia, Hellschreiber, AM, Packet, whatever. All these decoders could be running independently but together on the same band. <p> You could add a tool that shows a waterfall display of the same data on a web page, or play some of the decoded data to your headphones, or record it to disk, or do spectral analysis, all at the same time. <p> The information that you're processing is on the network once. You don't have to flood your network with multiple copies of the 40m band, the only limit is how much CPU power you can throw at this and to be frank, most computers on the globe today spend much of their time waiting for you to do something, so processing a bit of data like this is not going to tax anything built in the past 20 years or so. <p> The missing ingredient for this was a Linux tool called netcat, or nc. It allows us to distribute the information across the network using a technique called broadcasting. <p> So, RTL dongle, data extracted by a tool called rtl_sdr, distributed across the network using netcat and used by as many clients as you can think of. <p> The proof of concept I'm working on uses Docker to build a bunch of different containers, or clients if you like, that each can do a different task with the same stream. When I've got something to show and tell, you'll find it, predictably, on my GitHub page. <p> Oh, if you want to run the same thing for say the 80m band, you can. Now you have two network streams, one for 40m, one for 80m and as many decoders on your network as you have CPU cycles to play with. <p> If all this sounds like magic, you've seen nothing yet. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The sedentary myth of radio.
Foundations of Amateur Radio <p> When people think about and discuss my chosen hobby, amateur radio, there's often a perception that it's old men sitting behind a radio tapping on a Morse key, making beeping noises surrounded by all manner of imposing equipment, stacked thick and high in a tiny room that soon becomes too stifling to spend much time in. <p> While such scenes might exist, often reinforced by old photos and messy radio shacks, any self respecting amateur will tell you that plenty of time is spent outside the shack dealing with antennas, coax and earthing systems, combined with pouring concrete, building, erecting and climbing towers and a myriad of other physical activity. <p> My experience has shown that my own inertia bending acts often involve things like camping, portable operation in ever changing environments, throwing ropes into trees and recovering those later, erecting verticals, tying down squid-poles and other muscular movements like building temporary rotators lashed to the nearest utility vehicle to take advantage of a multi-band yagi that someone brought along to play with during a field day. <p> The first time I really discovered just how lacking my stamina is, was in early 2014 when the FT5ZM DXpedition team to Amsterdam Island was in town. I had the pleasure of spending a day with a couple of team members showing off the sights of my QTH, Perth in Western Australia. In the middle of the city is Kings Park. To give you a sense of scale, at over 400 hectares, Perth's Kings Park is larger than New York's Central Park and London's Hyde Park. One of the attractions is the dual spiral staircase DNA tower. At 15m height, it's the highest viewing point in Kings Park offering 360 degree views of the park and the city surrounding it. Commissioned in 1966, the tower has 101 steps and has recently been refurbished. It derives its name from the DNA Double Helix molecule, which is how the staircases are arranged. <p> One of my companions on the climb to the top was a sprightly amateur who's been licensed a decade longer than I've been alive. I marvelled when Arnie N6HC essentially ran up the tower when all I was able to achieve was puff my way up in his wake. <p> Since then I've discovered that doing 24 hour contests, camping and other fun stuff now absolutely kicks the stuffing out of me, often requiring that I spend a day in a small dark room recovering with a blanket over my head. While my body shape and my callsign have things in common and my doctor continues to encourage me to lose weight, I can say that my recent visit to hospital, unexpected as it was, reminded me in no uncertain terms that I should look after myself, if only so I can actually participate in the next contest or camp-out. <p> I'm not going to tell you what my fitness plan is, nor am I going to tell you to embark on one of your own, other than to ask, have you considered just how much of this wonderful hobby goes beyond keying a microphone or tapping a keyboard and consider just how safe you really are when you next climb up a ladder, tower or other height to fix an antenna? <p> Speaking of health, I've been absolutely blown away by the incoming messages, offers of help, shared gallbladder emergency and post-operative experiences and more, from people whom I've known for years through to amateurs who took a chance to introduce themselves and wish me well. It wasn't until this week that I really understood that this community is rich in personal lived history, going well beyond the experiences I've had outside the hobby. I'm ever so grateful for your encouragement and intend to keep fighting to get well. It's going to take some time, but I'm looking forward to when I can next camp-out and not regret my life choices. <p> So, get off your sedentary and go do something will ya? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Setting a little personal challenge ...
Foundations of Amateur Radio <p> A week ago I unexpectedly had my gallbladder removed. As emergencies go, I was lucky to be in a major metropolitan area with a remarkable hospital, supported by a group of humanity whom I've never much interacted with in my life. The staff at Sir Charles Gairdner Hospital were without exception amazing, from the orderlies to the nurses and everyone behind those, I interacted with about fifty people directly during my stay and every single person had a smile to share and an encouraging word to give. As life experiences go it was as uplifting as I've ever had the opportunity to celebrate. Sure it hurt like hell and there were things I'd rather not have to try again, but on the whole it was, if not pleasant, at least memorable. Recovery is going to take a little while and I understand my voice is expected to return to normal in a few weeks having been intubated for most of a day. <p> Half an hour after being discharged from my five days in hospital I was faced with a choice. Produce nothing for my weekly contribution to our hobby and face the risk of an astronomical bill from my hosting provider because the script that I wrote didn't foresee that there might be a time when I was unable to provide content, or produce something that, to be sure, was lacking in every way, but at least know that there wouldn't be a surprise waiting on my bank statement next month. So, my inadequate production saw the light of day. For that I apologise, it should have been silence. <p> During the week I returned to my shack and had a look at my beacon. As you might recall, I've been using Weak Signal Propagation Reports, or WSPR in my shack for a while. According to the logs the very first time was in November of 2017. At the end of last year I took delivery of a ZachTek desktop WSPR transmitter which has been reported on air over 16 thousand times since. I've only been using the 10m band and it's been heard as far away from me in Western Australia as the Canary Islands, the home of Johann EA8/DF4UE and Peter EA8BFK who between them reported my signal nearly 90 times. It's remarkable to note that this is a distance of over 15 thousand kilometres, on the 10m band, using only 200 mW. <p> During the week I made another milestone, a report in the opposite direction, across the Pacific Ocean to mainland USA. While that didn't break any distance records, it was a thrill to see a report from the Maritime Radio Historical Society, logging WSPR signals using KPH. <p> Other things to note about these reports are that its been heard across 81 different grid squares, by 144 different stations from all directions of the compass. <p> During my hospital stay and since, I've come to appreciate setting little goals. Little personal achievements that in and of themselves are not meaningful to anyone but me, and in some cases, my medical support team. It reminded me of a time when I attempted to achieve this in amateur radio, making a contact every day. Looking back over my logs I can tell you that I've not managed to maintain that, though, technically, on average, given that I host a weekly net and there's generally more than seven people who join in, I could claim an average of one QSO per day, but both you and I would know that I was stretching the truth somewhat. <p> It occurred to me that my signal report by KPH could be considered the beginning of my new 10m adventures. Much of my start in this hobby was during the previous solar cycle and the 10m band featured heavily in much of my activities, especially since you can get on that band with the very minimum of antenna, a quarter wave on 10m is a 2.5m whip and that can fit even on my car and it did, for years. <p> When the solar cycle eventually wound its way down, the 10m band was quiet for much of the year with the odd spot to whet your appetite, but rare enough to have little in the way of ongoing contacts. <p> As far as I'm concerned, 10m is back in play and it's my personal special band, so I'm setting myself a little challenge for the month of November and you can join in, open to anyone who wants to play. There's no prize, no scoreboard, no accolades, no nothing, other than the personal satisfaction of achievement. <p> Here's the challenge. How many kilometres per Watt can you achieve during November? To explain, my beacon uses 200 milliwatts, so any distance is multiplied by five to get the km/W number. If you use more than a Watt, you'll need to divide your distance by the number of Watts you use. As I said, this is a personal challenge. I'm not going to adjudicate, there's no rules to break, no one to tell you that you're cheating, it's just between you and your WSPR beacon. <p> For now, my record is 75630 km per Watt. I'm going to take the opportunity to consider what I might do to improve on that. Perhaps if I reduce power I'll still be heard in the Canary Islands, but I'll have more bang for my buck. Time will tell. Feel free to share your own achievement, or keep it to yourself, entirely up to you. <p> In case you're wondering about the capacitor thing, a gallbladder is like a bile capacitor, the analogy came from a story I wrote whilst in hospital, it might even see the light of day... <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

This space left intentionally blank
Foundations of Amateur Radio <p> Forgive my briefness. You'll discover why this space was left intentionally blank next week. It involves a broken capacitor, of sorts. <p> <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The Amateur's Code for future generations...
Foundations of Amateur Radio <p> Over the past while I've been discussing the Amateur's Code and its place in our community. I've shown that it was published in 1927, despite credits to the contrary and it's possible that it existed since 1923. I've discussed the original code, how it evolved and what changes have been made across the decades since. <p> I'd like to take this opportunity to compare the original from 1927 to a revision that I've constructed using the various versions that have been published since. Originally I was going to use the current 2022 version in the ARRL handbook to discuss this, but it's completely different from the one shown on the ARRL website today, which appears to be more recent, that it made little sense to pick one over the other. <p> Back to 1927, or 1923 if you like, written by Paul M. Segal 9EEA, or W9EEA, Director, Rocky Mountain Division and General Counsel of ARRL. <p> The Amateur's Code <p> I - The Amateur is Gentlemanly. He never knowingly uses the air for his own amusement in such a way as to lessen the pleasure of others. He abides by the pledges given by the A.R.R.L. in his behalf to the public and the Government. <p> II - The Amateur is Loyal. He owes his amateur radio to the American Radio Relay League, and he offers it his unswerving loyalty. <p> III - The Amateur is Progressive. He keeps his station abreast of science. It is built well and efficiently. His operating practice is clean and regular. <p> IV - The Amateur is Friendly. Slow and patient sending when requested, friendly advice and counsel to the beginner, kindly assistance and cooperation for the broadcast listener: these are marks of the amateur spirit. <p> V - The Amateur is Balanced. Radio is his hobby. He never allows it to interfere with any of the duties he owes to his home, his job, his school or his community. <p> VI - The Amateur is Patriotic. His knowledge and his station are always ready for the service of his country and his community. <p> It has a certain "quality" about it. Leaving aside that it's written with a male radio amateur in mind, it represents what the character Dennis Denuto in the 1997 Australian movie "The Castle" refers to as "It's just the vibe of the thing". <p> I present to you an updated version of the code in an attempt at preserving that vibe whilst taking into account that we're not in 1923 any longer: <p> The Radio Amateur is CONSIDERATE and RESPECTFUL...never knowingly behaving in such a way as to lessen the pleasure of others. <p> The Radio Amateur is LOYAL...offering encouragement and participation to the global amateur community. <p> The Radio Amateur is PROGRESSIVE...keeping abreast of science, striving to build and operate their station above reproach. <p> The Radio Amateur is FRIENDLY...patient; offering friendly advice and counsel to the beginner; kindly assistance, cooperation and consideration for the interests of others. These are the hallmarks of the amateur spirit. <p> The Radio Amateur is BALANCED...radio is a hobby, never allowing it to interfere with any of the duties owed to home, work, school or community. <p> The Radio Amateur is SUPPORTIVE...knowledge, station and skills always ready for service to country and community. <p> Hopefully you've followed along with the evolution of this discussion and find the reasoning for it as compelling as I do. Of course this is just one perspective on what a revised Amateur's Code might look like and I am offering it as a topic of discussion to the entire global amateur radio community. I hope that it provides food for thought, talking points and encouragement to ask questions. <p> I will reiterate my thanks to the WorldRadioHistory.com website where you can find many of the earliest editions of the ARRL handbook. If you have any of the missing editions, or better copies than those available, I'd encourage you to share them to continue to preserve the history of our community. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The Patriot in Amateur Radio
Foundations of Amateur Radio <p> It's been a while since I looked up the word "patriotic". Depending on which dictionary definition you use it could be: "showing love for your country and being proud of it", or it could mean: "having or expressing devotion to and vigorous support of one's country". <p> Synonyms for the word patriotic include "nationalist" and "nationalistic" and it relates to words such as "chauvinist", "jingoist" and "fervent". Jingoist means having or showing excessive favouritism towards one's own country. <p> That said, the original Amateur's Code published in 1927 says that: <p> The Amateur is Patriotic. His knowledge and his station are always ready for the service of his country and his community. <p> The 2022 ARRL handbook says: <p> The Radio Amateur is PATRIOTIC...station and skill always ready for service to country and community. <p> The ARRL website is slightly different: <p> The Radio Amateur is PATRIOTIC...His/[Her] station and skills are always ready for service to country and community. <p> Based on the meaning and connotations of the word "patriotic", I think that the sixth clause of the Amateur's Code is a political statement. It came at the close of World War One and in that context it makes sense. <p> I will also note that the word "patriotic" means different things to different people. For some it's a positive concept, for others it's the opposite and I think as a result it's a problematic concept in the world today. <p> If that's not clear to you, consider the notion of patriotic to a person living in the United States of America versus a person living in Ukraine, or a person living in North Korea, Sudan, China or Japan. Each of these countries have different concepts of the idea of patriotic which might not actually be compatible with each other. <p> Should we as a global community encourage cohesion or encourage incompatibility? <p> A more inclusive word might be "loyal", but we've already covered that. I've offered the following revision of the original loyalty clause to be: <p> The Radio Amateur is LOYAL...offering encouragement and participation to the global amateur community. <p> We could add the word country to that and dispense with the patriotic clause altogether, but I think that detracts from what the sixth clause is attempting to achieve, the sharing of station and skill to country and community. <p> What if we replace the word "patriotic" with "supportive" instead? I also think that the lost word "knowledge" is separate from station and skill and I think it has a place in this clause. <p> The clause would read: <p> The Radio Amateur is SUPPORTIVE...knowledge, station and skills always ready for service to country and community. <p> I'm aware that, given the wide range of meanings for the word "patriotic" across Earth, this is likely to be controversial, but in considering this version, please consider the level of emotion included in your feeling of the word "patriotic" versus the emotion for the word "supportive". It seems to me that reducing the level of emotion in a code of conduct is a positive evolution. <p> What are your thoughts on the matter? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Finding balance in Amateur Radio
Foundations of Amateur Radio <p> When you are absorbed in a hobby like amateur radio it's easy to lose track of the world around you. I freely admit to spending many hours on this hobby and it wasn't until I spent some effort taking stock that I discovered just how much time I spent. <p> The fifth clause of the Amateur's Code attempts to formalise this behaviour and I confess that it's taken me several years to find a more reasonable balance. Let's review the original 1927 published version of this clause. It reads: <p> The Amateur is Balanced. Radio is his hobby. He never allows it to interfere with any of the duties he owes to his home, his job, his school or his community. <p> It's interesting to note that in one of the oldest documents describing our community it refers to our activity as being a hobby. I'm noting this because there have been plenty of treatises written on the notion that amateur radio is a public service and not a hobby. <p> This clearly states that in the opinion of the General Counsel of the ARRL in 1927, Amateur Radio is a hobby and frankly, I'm fine with that. <p> The 2022 ARRL handbook removes the reference to hobby and words it: <p> The Radio Amateur is BALANCED...radio is an avocation, never interfering with duties owed to family, job, school or community. <p> The ARRL website reintroduces the concept of a hobby like this: <p> The Radio Amateur is BALANCED...Radio is a hobby, never interfering with duties owed to family, job, school or community. <p> I'll note that the definition of avocation is "a hobby or minor occupation" and I'm not sure what the clause gains by using a word that I had to look up in the dictionary. Consider for a moment if your first language isn't English, why use "avocation" when "hobby" is the same thing? <p> The original used the phrase: "never allows it to interfere with any of the duties he owes", this puts amateur radio as a hobby at the bottom of the pecking order in the list of things you do. The 2022 version waters this down to "never interfering with duties owed", essentially elevating the hobby above some of those other duties. I don't think that this is an improvement. <p> I'm a fan of amateur radio, but I think that in the scheme of things it needs to take the place of a hobby, not an activity that has the ability to be prioritised over any of your other duties. If it does, where is the line? What is more important and what isn't? Should this be something that we in our code of conduct endorse? What's next, telling amateurs specifically what they should be doing? I think not. <p> One thing that's worth exploring is the concept of "job". A job is your occupation, tow truck driver, radio astronomer, submariner or accountant. The original meaning, going back to the 1550's is "an activity that an individual performs in exchange for a specific fee or payment". <p> What if you don't have a job? What if you're retired, unemployed or have some other lifestyle? <p> What if we replace the word "job" with "work", defined as "a physical or mental activity that is performed in order to accomplish or produce something"? <p> This could make the fifth clause look like this: <p> The Radio Amateur is BALANCED...radio is a hobby, never allowing it to interfere with any of the duties owed to home, work, school or community. <p> It's short and sweet, uses simple language and it covers everything that the original document was attempting to achieve, and as a bonus it no longer requires you to have a job. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Being friendly in Amateur Radio
Foundations of Amateur Radio <p> The fourth clause of the original Amateur's Code, published in 1927 has a lot to say about the tone of amateur radio. It says: <p> The Amateur is Friendly. Slow and patient sending when requested, friendly advice and counsel to the beginner, kindly assistance and cooperation for the broadcast listener: these are marks of the amateur spirit. <p> The 2022 ARRL handbook tweaks that into: <p> The Radio Amateur is FRIENDLY...slow and patient operating when requested; friendly advice and counsel to the beginner; kindly assistance, cooperation and consideration for the interests of others. These are the hallmarks of the amateur spirit. <p> The ARRL website adds a pronoun and updates some of the language: <p> The Radio Amateur is FRIENDLY...He/[She] operates slowly and patiently when requested; offers friendly advice and counsel to beginners; kind assistance, cooperation and consideration for the interests of others. These are the marks of the amateur spirit. <p> I'm not quite sure what the idea behind this change is. The original referred to "slow and patient sending" in an era when that meant slowing down your Morse Code. I'm not sure what "operating slowly" means, unless it's asking the amateur to speak slowly or to operate their fixed speed FT8 station slowly, hardly the same thing as reducing the speed of your Morse key. <p> There's also a reference to the "broadcast listener", something which we refer to as shortwave listeners today. Essentially, be kind to the people around you and accommodate their limitations when you are asked, which is what the rest of the words have been morphed into. <p> I think that being friendly and patient is a worthy aim and I don't think that it should be requested. The original used the word friendly twice, added kindly and used counsel, advice, assistance and cooperation. <p> All this is collaborative language, encouraging the amateur to participate and being friendly and considerate when they do. <p> I also note the difference between a "mark" and a "hallmark". The word hallmark means a mark stamped on articles of gold, silver, or platinum by the British assay offices, certifying their standard of purity. <p> I think that certifying friendliness to a standard of purity is a worthy objective and I think that using the word "hallmark" instead of "mark" elevates the clause to a standard worth achieving. I think that the 2022 ARRL handbook use of the word "hallmark" is an example of an improvement of the code that should be embraced. <p> With that in mind, removing the superfluous pronouns, given that "The Radio Amateur" encompasses anyone with a license, here's an alternative for the fourth clause of the Amateur's Code. <p> The Radio Amateur is FRIENDLY...patient; offering friendly advice and counsel to the beginner; kindly assistance, cooperation and consideration for the interests of others. These are the hallmarks of the amateur spirit. <p> It's a little longer than I'd like, but I think it leaves less room for ambiguity in the notion of operating slowly and it no longer requires that someone needs to ask for an amateur to be patient. I think that overall, it encourages good behaviour in a world where we can bash out an angry reply at the whim of the nearest keyboard. <p> What do you like about this version and what would you change? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Progressiveness in Amateur Radio
Foundations of Amateur Radio <p> The third clause of the original Amateur's Code reads: <p> The Amateur is Progressive. He keeps his station abreast of science. It is built well and efficiently. His operating practice is clean and regular. <p> The 2022 ARRL handbook is similar: <p> The Radio Amateur is PROGRESSIVE...with knowledge abreast of science, a well-built and efficient station and operation above reproach. <p> The ARRL website adds in some pronouns and removes the science from the clause: <p> The Radio Amateur is PROGRESSIVE...He/[She] keeps his/[her] station up to date. It is well-built and efficient. His/[Her] operating practice is above reproach. <p> I'm not sure what prompted this alteration and frankly, I'm not a fan. Pronouns aside, science is at the heart of what it is that we do and that has been the case since the very first amateur went on air. It's also bewildering to me that knowledge and science has been transformed into keeping your station up to date, which means something else entirely. <p> The original is about learning and education, in my opinion the ARRL website version is about shopping and frankly it's distasteful in a world where we as amateurs are renowned for experimentation and constructing a solution from parts. <p> It raises another question. <p> Who actually made this change and what process exists to actually implement it? Is it the whim of an individual, or is there a committee that was elected to investigate and update the code? If it was an elected body, how does it represent me in Australia and how does it represent any amateur beyond the shores of the United States, or even beyond the membership of the ARRL? <p> Consider the scope of amateur radio as a global activity. The Amateur's Code has spread far and wide in the past century, well beyond its apparent origins as a page in the third edition of the ARRL handbook in 1927. <p> In my opinion this code is not an ARRL owned document, it belongs to all amateurs across Earth and it should be treated as such. As I've said before, it's a living document and it has evolved over time, but that doesn't mean it can be changed on a whim. There should be rigorous discussion in a public forum that informs any such change and at present I see no evidence of that at all. <p> To illustrate its reach further, the IARU has a document called "Ethics and Operating Procedures for the Radio Amateur", with Edition 3 published in 2010. It contains a copy of the code with yet another version of clause three: <p> The Radio Amateur is PROGRESSIVE... He keeps his station up to date. It is well-built and efficient. His operating practice is above reproach. <p> Clearly change is being implemented somewhere and it might well be that this version informed the current version on the ARRL website, 12 years later. I'll also note that there is a copyright statement in that IARU document that contains a whole lot of, in my opinion, unenforceable verbiage, including the requirement that any copy or portion is required to include a copyright notice, which in the case of the included Amateur's Code is murky at best. I also note that it credits Paul Segal in 1928, something which we've already established is wrong, given that the code appears in print in 1927 and has been credited to him as far back as 1923. <p> Back to the clause, I think that keeping science as an integral part of the conversation is essential. I'm going to repeat the original clause as published for reference. <p> The Amateur is Progressive. He keeps his station abreast of science. It is built well and efficiently. His operating practice is clean and regular. <p> In addition to science, there's a statement about how to build and how to operate. It's a little curious to use the word progressive, but it means to happen or develop gradually or in stages. In other words, you don't need to be perfect on day one, but you do need to strive for the objectives as part of an evolutionary process. <p> So, progressive, science, well built and well operated. That seems like a recipe for lifelong learning, in my opinion a lofty goal to strive for. <p> What if we lost the last century pronouns, removed the shopping imperative and kept the tone: <p> The Radio Amateur is PROGRESSIVE...keeping abreast of science, striving to build and operate their station above reproach. <p> Would such a clause inspire you to do better, to build and grow as an amateur, to improve and learn? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Loyalty in Amateur Radio
Foundations of Amateur Radio <p> The second clause of the original Amateur's Code reads: <p> The Amateur is Loyal. He owes his amateur radio to the American Radio Relay League, and he offers it his unswerving loyalty. <p> The 2022 ARRL handbook presents it with the following words: <p> The Radio Amateur is LOYAL...offers loyalty, encouragement and support to other amateurs, local clubs and the American Radio Relay League, through which Amateur Radio in the United States is represented nationally and internationally. <p> The ARRL website goes the extra mile to make this hard work and states that: <p> The Radio Amateur is LOYAL...He/[She] offers loyalty, encouragement and support to other amateurs, local clubs, the IARU Radio Society in his/[her] country, through which Amateur Radio in his/[her] country is represented nationally and internationally. <p> Pronouns aside, this has got to be one of the more tortured efforts you might subject an entire group of humans to. Written in an attempt to enumerate each and every specific version of the global amateur radio community, it excludes more than it includes and in doing so completely fails the one thing it aims to achieve, a sense of belonging, being part of something bigger than you. <p> So what does loyalty look like? <p> Is providing constructive feedback loyalty? Is giving your time and energy a loyal thing? What about being a member of a club? <p> The dictionary suggests that loyalty is a strong feeling of support or allegiance. Originally the code suggested that this should be directed at the ARRL, even the handbook continues to suggest that today, but is that relevant for me here in Australia? Should I be a loyal member of the ARRL, or should I be a loyal member of the WIA? What if there is a second body in your country? In Australia there is another organisation attempting to reshape the hobby, RASA, the Radio Amateur Society of Australia, should I be loyal to that? Can I be loyal to both, or neither? What happens if I am not comfortable with either organisation, who should I be loyal to? <p> National bodies aside, what about clubs? Am I required to be a club member and be loyal to it? What if I'm a member of more than one club? Should I be more loyal to one than the other? Should I be more loyal to the national body or my local club? What if I'm not a member of any club? What should I be loyal to then? <p> What if loyalty is coupled to an idea instead of a specific body? What might that idea look like? The revised version of the clause already includes concepts such as encouragement and support to other amateurs. What if we just omit any specific bodies and replace it with the idea of the global amateur community in all its many splendored diversity? <p> While we're looking at this, the word encouragement includes the action of giving someone support, confidence or hope, so we're repeating ourselves by using support and there's plenty of other things we could share around. <p> Here's a philosophical question to wrap your mind around. If you have a drivers' license, but you don't drive, are you a driver? Similarly, if you have an amateur license, but you don't do anything with it, are you an amateur? Perhaps the nub of this lies in participation. <p> Taking those thoughts into account, we could rephrase the second clause of the Amateur's Code to: <p> The Radio Amateur is LOYAL...offering encouragement and participation to the global amateur community. <p> If this clause was part of the Amateur's Code, would it help you feel like you belonged, would it travel beyond the borders of your country and would you feel part of something bigger? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Consideration in Amateur Radio
Foundations of Amateur Radio <p> The first clause of the original Amateur's Code reads: <p> The Amateur is Gentlemanly. He never knowingly uses the air for his own amusement in such a way as to lessen the pleasure of others. He abides by the pledges given by the A.R.R.L. in his behalf to the public and the Government. <p> The 2022 ARRL handbook version states it like this: <p> The Radio Amateur is CONSIDERATE...never knowingly operates in such a way as to lessen the pleasure of others. <p> Today the ARRL website presents it as: <p> The Radio Amateur is CONSIDERATE...He/[She] never knowingly operates in such a way as to lessen the pleasure of others. <p> It's surprising to see the addition of the He/[She] pronoun when nothing is added by doing so, in fact for some amateurs this actually reduces its relevance, something which I've spoken about before. <p> We could just simply change the words to remove the pronoun entirely, but does that actually cover all of what we want it to mean? Should this consideration be limited to operating, or should we go beyond that? What about conduct in a club setting, or on social media, email or SMS? <p> Some of these activities are conducted as a radio amateur and some are not. If we're limiting ourselves to amateur radio, not an unreasonable place to start given that we're talking about a document called "The Amateur's Code", we should really discuss the nature of amateur radio today. <p> I find myself in a community of amateurs, not a radio in sight, exchanging thoughts, opinions and experience that go beyond the concept of operating. I will note that there are legal definitions in our hobby that describe the notion of operating that do not include QRZ.com, email or Reddit and there is an argument to be made that operating falls strictly within the bounds of a licensed amateur activity. <p> That said, since "no man is an island", first uttered in 1624 by John Donne, neatly illustrates that although we're licensed amateurs, we do more than key our radios alone and even when we do, there are activities that affect others who are not operating as such. <p> When we discuss things with each other, face to face, that's not a licensed activity, even if both of us are amateurs. Neither is sending an email to another amateur, or commenting on a social media post. Standing in a club and teaching is also not a licensed amateur activity and cannot be considered under the idea of "operating". <p> All of what this clause is attempting to say is to be considerate. Don't reduce the pleasure of others by doing things that are unacceptable. It goes to how you are expected to be, to conduct yourself, to behave. <p> To incorporate this idea that what you do with other amateurs goes beyond operating, I think the word "operate" needs to be changed to the word "behave". <p> I'd also like to explore the word "gentlemanly" from the original text. Synonyms for this include civilised, courteous, honourable and polite to name a few. It seems to me that words like that would benefit our interactions within our community, not to mention beyond it. <p> One word that comes to mind is "respectful", something that lies at the heart of how we conduct ourselves towards each other. <p> So, if we drop the pronouns, update the word operates and add in respect, a revised clause one could be: <p> The Radio Amateur is CONSIDERATE and RESPECTFUL...never knowingly behaving in such a way as to lessen the pleasure of others. <p> Let me hasten to point out that I'm proposing this as a starting point for discussion. This is an activity that should go beyond one individual, it should also go beyond a single organisation. Amateur Radio is a global activity and it would do well for us to consider all of humanity when drafting a code of conduct which is essentially what the Amateur's Code is attempting to achieve. <p> So, how would you approach the first clause, what do you like, what do you think is missing, what would it need for you to consider it words to live by? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

A code for amateurs
Foundations of Amateur Radio <p> The American Radio Relay League or ARRL is one of the oldest amateur associations on Earth. 1926 saw the birth of "the Radio Amateur's Handbook", the first edition of what we now know as "The ARRL Handbook For Radio Communications" featured chapters on what it means to be an amateur, how to build and operate a station, how propagation works and how to experiment. The very first handbook had 5000 copies printed and thanks to the website WorldRadioHistory.com we have access to a signed copy by the author himself, the Communications Manager of the ARRL, Francis Edward Handy (W1BDI). He starts the 228 page book with the following words: <p> This Handbook is written as a guide for member-operators of the League. It is also useful as a source of information to the man who wants to take part in amateur radio activity but who has no idea of how to get started. Written first of all for the beginner, such an amount of useful and up-to-date information has been added that the Handbook in its present form is equally valuable as a compendium of information for the experienced brass-pounder and the beginner alike. <p> The first edition doesn't show a cover price, but the third edition, published a year later shows a charge of $1. The 2022, or 99th edition has nearly six times as many pages, 1280 of them, it costs ten times as much per page and sells for nearly 50 times as much at $49.95. The current handbook features topics such as Radio electronics theory and principles, Circuit design and equipment as well as articles and projects that include 3D printing, portable battery selection, safe antenna and tower work practices and comes in a variety of formats including electronic and box sets. <p> I'm giving this background to give you a sense of how things have evolved in the past century. For example, one thing that the very first edition didn't have was a page called the Amateur's Code. The oldest copy I've found appears in the 1927 or third edition. <p> If you're familiar with the words, you're in for a treat. If not, sit back and imagine it's 1927, or 1923, more on that in a moment. <p> The Amateur's Code <p> I - The Amateur is Gentlemanly. He never knowingly uses the air for his own amusement in such a way as to lessen the pleasure of others. He abides by the pledges given by the A.R.R.L. in his behalf to the public and the Government. <p> II - The Amateur is Loyal. He owes his amateur radio to the American Radio Relay League, and he offers it his unswerving loyalty. <p> III - The Amateur is Progressive. He keeps his station abreast of science. It is built well and efficiently. His operating practice is clean and regular. <p> IV - The Amateur is Friendly. Slow and patient sending when requested, friendly advice and counsel to the beginner, kindly assistance and cooperation for the broadcast listener: these are marks of the amateur spirit. <p> V - The Amateur is Balanced. Radio is his hobby. He never allows it to interfere with any of the duties he owes to his home, his job, his school or his community. <p> VI - The Amateur is Patriotic. His knowledge and his station are always ready for the service of his country and his community. <p> This version is credited to Paul M. Segal 9EEA, Director, Rocky Mountain Division ARRL. <p> The code appears on page 9 of the 1927 edition of the handbook. It uses Roman numerals to identify each point, the title is beautifully rendered with the Old English Typeface and it's shown inside a rectangle on a page on its own. <p> Over the next 45 years the text stays the same. There are changes like colons to semi-colons, an additional comma and the evolution from Roman numerals to modern numbers, and then written numbers and finally the removal of the numbers entirely. At one point the title is changed from "Amateur's Code" to "Our Code", but that only lasts for one edition. Speaking of editions, the 1936 edition, the thirteenth in the series, is referred throughout as the 1936 edition, superstition is alive and well. <p> The credit changes over time as well. In 1929 Paul's callsign is changed from 9EEA to W9EEA. <p> In 1943 we see a once-off credit appear. It states that the code was written in 1923 by Lieut.-Commander Paul. M. Segal, General Counsel of ARRL. It's the only credit that shows a different year from any of the other references which all point at 1928 as the original year, which is what the ARRL uses today. Interestingly, we have a copy of the handbook from 1927 that features the code, so it's entirely possible that 1923 is actually correct and it's not hard to imagine that a poorly printed 3 looks like the remains of the number 8. <p> To add to this, there's a 1944 FCC report to the President of the United States of America that contains a reference to "Lieutenant Commander Paul. M. Segal, the radio industry attorney". In addition there's an announcement in the New York Times, dated 25 May 1968 with the headline: "Paul M. Segal Is Dead at 68; Expert in Communications Law" <p> I don't have access to any version of the Second Edition of the handbook which had two print runs in 1927. It's entirely possible that the code appeared there, but I have no evidence either way. I do believe that Paul M. Segal, 9EEA Director of the Rocky Mountain Division of the ARRL is the same person as Lieutenant Commander Paul. M. Segal, General Counsel of ARRL and radio industry attorney who became a silent key in 1968. <p> Credits, layout and font changes aside, 1973 sees the first time when the words of the Amateur's Code actually change. <p> Let me illustrate. <p> The original first clause reads: <p> I - The Amateur is Gentlemanly. He never knowingly uses the air for his own amusement in such a way as to lessen the pleasure of others. He abides by the pledges given by the A.R.R.L. in his behalf to the public and the Government. <p> In 1973 that's changed to: <p> One The Amateur is considerate . . .He never knowingly uses the air in such a way as to lessen the pleasure of others. <p> The first four clauses are modified to greater and lesser degree, clause five and six stay the same. <p> Today the ARRL website shows the first clause as: <p> The Radio Amateur is CONSIDERATE...He/[She] never knowingly operates in such a way as to lessen the pleasure of others. <p> And the credit reads: "adapted from the original Amateur's Code, written by Paul M. Segal, W9EEA, in 1928" <p> It's noteworthy that going back to the original text the very first clause encourages the amateur to be gentlemanly, something which we can relate to in terms of being respectful, polite and civil. <p> It's also clear that the Amateur's Code is a living document and has been moving with the times. I think that we as a community have the opportunity to participate in another review and I will investigate and share with you some of my thoughts on the matter. <p> I think that it is important that we have a code of conduct that reflects our values and at present the best starting point we have is the Amateur's Code. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The microphone gain game ...
Foundations of Amateur Radio <p> One of the most misunderstood settings on your radio is the microphone gain. You'll often hear people talking about adjusting it up or down depending on what they hear and the results are often displeasing to the ear. <p> The very first thing to know is that the microphone gain is likely the single most audible setting on your radio, right after the tuning frequency. It's pretty much the first variable between your voice and your transmitter. Set it too low and you'll hear nothing, set it too high and you'll hear gibberish. <p> I said it's pretty much the first thing, but it's not the very first. That's your voice, unique in all its glory, loud, soft, happy, sad, funny or not, it's the thing that your microphone captures to transmit. Closely coupled to your voice is the distance between your mouth and your mike. The closer you are, the louder, the further, the softer and the more background noise creeps in. <p> As an aside, speaking of noise, there's background noise at play, but there's also the noise that comes from the audio circuitry itself, which can for example change depending on the temperature of your radio. I'm going to refer to both as noise here, even though they're slightly different. <p> So, starting with the ideal model where you always speak in the same way, at the same volume, at the same distance from the microphone, with a constant temperature in your radio, at all times, the next thing is the microphone gain, or gain. <p> Gain is an imperfect attempt at corralling your utterings into electrical signals without causing the audio circuit to distort or drown in noise. Distortion comes as a result of overloading of the audio circuit when the gain is too high, causing clipping, which essentially changes the audio waveform into something that no longer resembles your voice. At the low end of the gain range there is no difference between audio and noise which results in your voice being buried inside a hissing noise. <p> You might wonder why we don't just build transmitters that cannot clip and increase your volume. Well, we do. We use things like AGC, or Automatic Gain Control to attempt to prevent such things from happening, but this isn't perfect. <p> All this results in the microphone gain being a setting that you need to tune to your voice and adjust as things change. Overall, the best outcome is when you set the gain so the AGC just engages when you talk normally. <p> This gain setting also applies to computer generated signals, often fed into your radio via an audio or microphone input. If you set the gain too low, noise is the problem, set it too high and the Automatic Gain Control will distort the signal to the point where it no longer works and causes interference for everyone else including the station that you're trying to contact. <p> On older radios the output power was fixed. This is also true for Software Defined Radios. To reduce output power, you can change the microphone gain down and reduce the power. Change it to halfway and your output power is essentially reduced to half power. This works for a range of settings, but get too low and we're back to noise and audio fighting each other. <p> The opposite isn't true. <p> You cannot increase the microphone gain to increase power. The moment you exceed the audio circuit range your signal is distorted. On an SDR this means that you're exceeding the ability of the Analogue to Digital converter to represent your audio. In digital terms, zero means no sound and all on means 100%. If your audio is so loud as to only be 100% on, that's like sending a tone out the transmitter, resembling anything but your voice. <p> All of what I've talked about is related to SSB signals and to some extent AM. FM is a different animal entirely. For starters, output power on FM is fixed. The next difference is the signal or channel width. Without going into full detail, FM comes in different widths, WFM or Wideband FM, NFM, or Narrowband FM, and between the two, "normal" FM. To make things more fun, not everyone agrees on what each one means at any given time. Also, channel width and channel spacing are not the same thing, but that's for another day. <p> Gain aside for a moment, consider two matched FM radios using the same channel width. Your voice volume is determined by how much of the channel you use. Louder means wider, softer means narrower. Adjust the gain up, the signal gets wider, but the limit of the channel width remains, get too high and it clips at the channel width and distorts. At the other end, changing the gain down, you'll use less of the channel width and eventually the noise and your voice will be at the same level and you won't be heard. <p> Let's look at what happens when you use a normal FM signal to transmit to a narrowband FM receiver. Essentially your signal is too wide and the result is that your voice will be clipped unless you speak really softly or if you've set the gain really low, either way comes with more noise. <p> Similarly, if you transmit a narrowband FM signal to a normal FM receiver, then your voice will be very low, regardless of the microphone gain setting and turning it up will only distort it due to clipping inside your transmitter. <p> So, for FM, before fiddling with the gain, make sure that you're using the same FM mode as the other station. One thing to remember is when you use a repeater, if the audio is always too loud for everyone, your mode is probably too narrow. Similarly, if the audio is always too soft and you always need to turn up the volume on your radio, your mode is likely too wide. Check your radio specifications to determine what each mode means. <p> In broadcast audio this whole thing is managed by calibration using standard tones, but as amateurs we tend to rely on other people reporting their feelings on the quality of your voice with the often heard admonishment to adjust the microphone gain. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What's with the repeater offset again?
Foundations of Amateur Radio <p> As a new amateur one of the initial perplexing issues you're confronted with is setting up your first radio to talk to the local repeater. The question is so common that it's almost an invisible rite of passage to a new licensee. While I'm a fan of learning, there is plenty of that to go round and setting up your radio to talk to a repeater shouldn't be a hurdle to getting on air and making noise. <p> Ignoring the whole repeater thing for a moment, let's consider your radio. It doesn't matter if it's a handheld, a base station, a boat anchor or something else. To participate in the whole repeater experience, you need to tune your radio to hear it. <p> Technically, if I told you that you could tune to a local repeater on 146.750 MHz, that would be enough information to get you going, but this depends entirely on a set of standard assumptions that are likely not obvious to you. Let's explore what's going on. <p> Given that frequency, you can set your radio to 146.750 MHz and in most cases, you'll be able to hear the repeater. To actually participate, you would need to do some more work to get your transmitter to be heard. <p> As I said, standards are what makes that possible, but like every human endeavour, caution must be applied. As Andrew Tanenbaum said: "The nice thing about standards is that you have so many to choose from." With that in mind, let's proceed. Before you start yelling, I'll add caveats at the end. <p> Armed with a repeater frequency, you have enough information to get on air, but it assumes that you know a couple of things. So let's delve into those assumptions. <p> For starters, there is an assumption that you're aware that to operate a repeater you must transmit on a different frequency than what you're listening on. Why that is the case is a whole other discussion which I'll leave for today. <p> There is the assumption that you know that the two frequencies, one for listening, one for transmitting, are separated from each other by a known distance, a so-called offset. <p> You're also assumed to know that this offset is fixed but different for each band. <p> There's more, but let's start here. <p> For your radio to transmit on a different frequency than you listen, you must tell it to. In many cases tuning your radio to a so-called repeater frequency will already do this for you, but not always. <p> You might need to specifically program your radio for repeater operation, or turn on the offset mode, or use two memories, or some other thing specific to your radio. Read The Friendly Manual, I know you know how. <p> The next step is to look at the band you're on. In this case the 2m band. This means that the standard says that the difference between the receive and transmit frequency is 600 kHz. I'm studiously ignoring other bands at this moment because, standards. <p> At this point you know that your radio should be tuned to 146.750 MHz, it should be in repeater mode and the offset should be 600 kHz. That's when the next question arises, should that be plus 600 or minus 600? <p> Guess what, another standard. If the receive frequency is less than 147 MHz, the answer is minus 600 kHz. If it's more than 147 MHz, it's plus 600 kHz. <p> Notice that I didn't specify what happens if it's exactly 147 MHz? That's because nobody knows. Seriously though, the local repeater owner will know, but you can try either and get your answer. <p> Now for the caveats. <p> Let's start with the 147 MHz cross-over exception. This isn't global, for example repeaters in California use several different ranges for such a cross-over point. <p> I also didn't tell you about repeaters on other bands because the offset depends on where you are. In many cases the 70cm repeater offset is 5 MHz, but in Europe it's mostly 7.6 MHz, unless it's 9 MHz. The 10m repeater offsets are often 100 kHz, but sometimes they're 1 MHz, similarly the 6m repeater offset is 1 MHz, except when it's not. <p> The point being that starting with a receive frequency, there's a great number of assumptions, many of which you'll need to discover for your own location. A great resource which I've mentioned before is the brainchild of Garrett KD6KPC, the repeaterbook.com website and app, maintained by a global group of volunteers, which lists many repeaters and their specific settings, frequencies and locations. <p> So, armed with this knowledge, I expect that you can now find a local repeater and make use of it. When in doubt, contact the owner and ask for help, they're a friendly bunch. Remember to say thank you! <p> So, what excuse do you have not to get on air and make noise? <p> Oh, before I forget, if you don't hear anything, or if transmit isn't doing what you expect, check that you've configured CTCSS, another assumption. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Take a long hard look at our community ...
Foundations of Amateur Radio <p> The art of amateur radio is a globe spanning activity, held together by radio waves and the promise of a community with a shared uncommon interest. The strength of a community depends entirely on the members of that community. Without the efforts of each individual amateur, our worldwide license to experiment is doomed. <p> You might ask yourself what part you have to play in this? <p> Consider what would happen if a group of amateurs decided to transmit on an unlicensed frequency, or purposefully interfered with other legal users. It's obvious that the regulatory response to such illegal activities would be swift and left unchecked, it would spark the end of our hobby. <p> What prevents that from happening is our common purpose, our common interests, our willingness to address such behaviour, or said in another way, our community standards. It's the thing that keeps us talking, sharing, learning, experimenting and having fun along the way. <p> I've been told many times that I shouldn't expect all amateurs to be friends, but consider for a moment the sheer diversity of our community. For starters we're scattered around the planet. We have different cultural and political sensibilities, we have different religions and expectations. We don't even speak the same language, even if you forget that the Japanese station you just had a QSO with was using phonetics not even close to their native language. <p> Those differences are mostly attributes of geography, but they don't end there. We have differences in our households and family structures, our work life and finances, our play time and our interests. We also differ in age, skin colour, gender and even our sexuality, orientation and gender identity. <p> Even among all those differences, we are still radio amateurs together with our personal preferences for Icom, Yaesu, Kenwood or some other brand, our desire to use QRP or kilowatts, our need to use a Morse key, our voice, or a computer. We choose to use a repeater, or not, choose HF or not, like to chat, or not, build antennas, or not. <p> So it's with all those differences in mind that I'm distressed to report that yet another amateur has been bullied out of our community. An amateur who joyfully participated in this community, who made videos, wrote software, learnt and shared. Like others I know, she was bullied in our community because she was different and it's not the first time I've witnessed this behaviour and it's not the first time I've called out this unacceptable conduct by so-called members of our community. Different, how you ask? Does it really matter, or are you asking to determine if there was a valid reason for making her feel uncomfortable? <p> To be clear, our community is a welcoming environment, filled with hope and joy, but there is a small rotten element in our midst that we need to rip out root and branch, much like we would if it was deliberate HF interference. <p> You might think that given that this abuse exists on reddit, YouTube, Twitter, Facebook, QRZ, email, telephone, letterbox, in clubs and on-air, that it's a majority experience. That's not the case. The same individuals harass fellow amateurs across multiple platforms as entertainment causing untold harm to their victims. <p> The Standard You Walk Past Is The Standard You Accept. It's not just up to victims of bullying and harassment in a community to speak out. As members of our community, we amateurs have a responsibility to speak out also. Anyone who doesn't is part of the problem. Our community is so diverse as to never be one single thing. A bully is a bully, no matter which words are used to sugar coat it. <p> I'd like to invite you to consider any bullying you accepted in silence, either personally, as a witness, directly, or indirectly. This community is strong, it's resilient, it's resourceful, it's you and I and it's our duty to stand tall and speak out, loud and proud, about any victimisation. <p> Even if you've never considered that this is happening in your community, look around and notice people leaving the hobby unexpectedly and examine why that might be the case. <p> You might ask what it is that you can do to help. For starters, calling it out at every occurrence is part of communicating to the victim that they're not alone. It tells the community that they are part of the solution. It tells the bully that what they're doing is unacceptable. <p> I host a weekly net where we talk about amateur radio and discuss issues like this as and when they occur. We've done so in the past and will continue to offer a safe space for members of this community. <p> I have and continue to offer my email address, cq@vk6flab.com, for anyone who is struggling with this to discuss any bullying that they are dealing with. <p> I have experienced some of what this amateur has gone through at the hands of this community and I will not stand for it any longer and neither should you. Keeping quiet and changing frequency is not the solution as time after time experience has proven. <p> Calling out a bully and any bullying behaviour is calling out a vicious minuscule minority with a peanut brain who needs to be read the riot act. They are not welcome in this community. They are few and far between and we really don't need or want them in our midst. <p> In my opinion, the community must take ownership of this problem and address it directly, rather than sit on the fence and leave a victim wondering why they're on their own. If you are a victim of bullying in this community, I stand with you and if you are a bully, I'll do everything I can to call you out. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Much Ado About ...
Foundations of Amateur Radio <p> There are days that my brain just cannot keep up with all the ideas that I have spinning around and today is one such experience. Before I take you on this wild ride I will mention that I'm only going to focus on the amateur radio specific things going on, but I tend to have a couple of projects on the go at any one time, much like a messy desk piled high with paper, books, gadgets, parts and coffee cups, my mind has this sometimes exhausting tendency to see connections between various projects and often this results in deeper rabbit holes, so with that in mind, I'd like to make an attempt at describing all the amateur things that are going on at this very moment. <p> So, here goes, hang on! <p> It all started with two friends, independently and until now, unbeknownst to each other, playing with a mode called Digital Radio Mondiale, or DRM. It's something I've talked about before. One friend is trying to decode it, the other is trying to generate it. I'm sitting on the side cheering on because I think that there will come a time when I understand enough of my PlutoSDR that I can create any form of any mode and not be limited to the SSB bandwidth that current technologies use and be able to receive and generate say a 20 kHz DRM signal. <p> In order to advance my learning, I started the day wanting to describe a PlutoSDR project. I wanted to spend some enjoyable time playing, making some progress and then telling you about it. I did play, I did have fun, I did make progress, but trying to explain precisely what and how was where I came unstuck. <p> I began describing the difference between analogue and digital radios and how there's a fundamental difference in how a signal comes to exist in both. That quickly turned into a conversation about I/Q signals, a discussion that I've been putting off for a while because I'm still not happy with my own understanding of it, let alone any attempt to explain it to you in a coherent and hopefully fun way. <p> The complexity of explanation was brought home to me during the week when NASA Administrator Bill Nelson used an example to explain an image taken by the James Webb Space Telescope. <p> The phrase he used was this: <p> "if you held a grain of sand on the tip of your finger at arm's length, that is the part of the universe that you're seeing" <p> That seemed pretty clear to me. I could imagine a grain of sand on my fingertip, extending my arm and grasping the idea that hidden behind it was a small slice of the sky representing how big the image was. For me that explanation was excellent, especially when Bill Nelson went on to say that the things you were seeing were galaxies, each made of a hundred billion stars, each likely with planets in orbit. <p> Only I discovered that the explanation using a grain of sand wasn't universal. I was surprised to learn that for some it got muddled up with the grains of sand in the universe and the relationship between those and the one on your finger. <p> To be clear, I'm not saying that there is anything wrong with misunderstanding, but it reminded me in a visceral way that how we explain things matters and there are plenty of times when my own efforts fail to achieve their intended purpose, of making things easier to understand. <p> Given the importance of I/Q signals within the whole conversation on software defined radios, I don't want to do a half baked attempt and fail. I will say this, an I/Q signal is a way of precisely representing a radio signal, but only to stop you thinking about it further. <p> I was talking about how my mind accumulates things. <p> The NanoVNA that's sitting on my desk, gifted to me by a friend, is a fantastic example of the similarity between it, software defined radio and say a TinySA which I came across last week. Let me unpack that a little. <p> A NanoVNA is a piece of testing equipment, as is a TinySA. They test different things. Both have the ability to generate and measure a signal and in that they share the abilities of an amateur radio transceiver that can also generate and receive a signal. <p> That right there is a very deep rabbit hole, so I'm going to purposefully step away and continue the journey of observation, only pausing to mention that my PlutoSDR has all the same capabilities and in that it's not alone. <p> The fundamental difference between these three devices is software. There are a few other things, but on the whole, software. <p> So, I'm carrying around this mush of things that are almost the same, but different, almost understood, but not quite, almost ready to explain, but not yet. <p> In an attempt at going forwards by moving sideways, I went on to investigate other things, prompted by people who send me emails. For example, code plugs and DMR and frankly I felt unclean reading the various explanations. I'm a firm believer in Open Source and this is like asking an Icom owner to explain the benefits of using Yaesu hardware. <p> Another question was around bending antennas, as-in, what happens when you drive down the road and your VHF antenna bends, or what happens if your HF dipole is bent to fit in your garden. Superficially I can say that the antenna changes as its bounding box changes shape. That means that the feed point impedance will change, as will the resonant frequency. The radiation pattern will also be affected, but sitting down and discovering just by how much is going to take more time than I have available whilst attempting to string together some coherent words on a topic I love. <p> So, in an attempt at telling you what's going on in my world of amateur radio, I leave you with this question: <p> "What was I talking about again?" <p> Now I remember, this is about just how complex, fluid and interesting amateur radio is for me and in that observation lies why I'm here doing what I do. <p> "What makes you keep coming back for more?" <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The power supply connector dance contest...
Foundations of Amateur Radio <p> In over a decade of writing a weekly article about all manner of different aspects of our hobby and community, I've never once talked about power connectors for your radio. It's so universal as to be invisible and rarely discussed. So much so, that something you do out of habit, makes another stop dead in their tracks and ask themselves why they never thought of it. <p> Despite how you might feel at the time, there's no such thing as a stupid question. The other day a fellow amateur Dave VK6KV asked about a power connector he'd seen at the local electronics store. That question started a group discussion about powering radios and how best to achieve that. <p> The very first thing to discuss is that the vast majority of amateur radio transceivers expect a nominal voltage of 13.8 Volt DC. That might sound like a strange requirement, but it's the voltage that comes from a fully charged 12 Volt lead acid battery, which is what many radios use as a power reference. <p> The next thing to consider is that a transceiver can draw quite a bit of power when it's transmitting. My Yaesu FT-857D user manual suggests 22 Ampere, but I've never seen that in the decade it's been in my possession. <p> When you purchase a radio, you'll likely discover that it either comes with bare wires, or some random connector that doesn't fit anything else. In many cases I've discovered that people cut off that connector and replace it with whatever standard they've come up with in their shack, but when they take their kit out on a field day, or acquire a new radio, the problem starts all over again. <p> Let me suggest a different approach. <p> The Anderson Power company, founded in 1877 by brothers Albert and Johan Anderson in Boston Massachusetts, make a range of connectors called the Anderson Powerpole and they come in a variety of ratings, sizes, shapes and colours. <p> First introduced as a standard by the ARRL Emergency Communications Course in December of 2000, after previously being adopted by amateur operators in California, the Anderson Powerpole PP15/45 series was selected. The Coordinator for Hawaii State Civil Defense RACES, or Radio Amateur Civil Emergency Service, Ron, then AH6RH, now KH6D has a detailed description on his QSL page on how this came about. <p> As a result, the stackable, asymmetric, genderless plugs are in wide use within the amateur community. The plugs are designed to be joined together using various orientations, creating a unique connector to suit your purpose. The Amateur Radio Emergency Service or ARES standard is one such orientation and before you adopt the Anderson Powerpole in your shack, make sure you use their orientation to avoid magic smoke from escaping your equipment. <p> Picking a connector is just step one. <p> When you acquire a new piece of 12 Volt equipment, you can cut off the connector and replace it with the ARES Anderson Powerpole connector orientation. Many amateurs I know then throw away the unusable connector, or shove it into a box for later. <p> Instead, what I do is, terminate the plug that you just cut off in exactly the same way. Essentially, from a visual perspective, you've kept the power cable intact, but inserted a Powerpole join into the lead. As a result you now have a standard Powerpole power lead and you have a new Powerpole adaptor to suit the new connector. <p> For that reason alone, I tend to bring a box of spare Red and Black Powerpole connectors to any field day and use the opportunity to spread the love around. <p> As I said, the individual plugs come in a variety of colours, I have a selection of eleven in my shack, where for me a different colour means a different voltage or purpose. For example, I've adopted green as the colour for antenna radials. <p> One challenge I'd not been able to resolve, until suggested by Ben VK6NCB, was how to avoid plugging a 12 Volt power supply into something that expects say 7.5 Volts. Colour alone isn't sufficiently idiot proof, especially in the dark. Ben suggested that I adjust the orientation of the plugs, preventing connectors of different colours to mate. Looking back, I can't understand why I didn't think of that in the decade I've been using them. <p> I will note that there are other Anderson connectors in use. A popular one is the grey double connector, used in portable solar installations and caravans. I'd recommend that you consider if you really want to plug your radio directly into a solar panel or not and choose your connectors accordingly. <p> Before you ask, to my knowledge the Anderson Power Company doesn't know I exist, nor did I get compensated in any way to say Anderson Powerpole. It's the ARRL Emergency Services standard and I'm happy to advocate for its use everywhere I go. <p> So, whether you're using bare wires, banana plugs, Molex connectors or some other random barrel connectors, consider cutting the lead and inserting Anderson Powerpole connectors. <p> When was the last time that you had to do the 12 Volt connector dance? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Defining a standard on Contest Scoring
Foundations of Amateur Radio <p> Not a weekend goes by without an amateur radio contest or six, each with its own objectives, audience, times, rules, exchanges and scores. When you get bitten by the contesting bug, you'll quickly graduate from using pen and paper to keyboard and screen. That process comes with the inevitable selection of software suitable to both run on your shack computer and log your particular contest since as you'll discover, not all software knows about all contests or runs on every computer. <p> When you eventually do arrive at a working solution, you'll reap the rewards of using technology. Contesting software can help in many different ways. From logging your operating frequency and mode to tracking where other stations are active and it doesn't stop there. Type in a partial callsign and your software can suggest which ones it might be. Log a contact and you'll see if your contact is valid within the rules or not. Software can track your activity level and warn if you're exceeding any contest time limits. It can keep track of multipliers and the impact on your total score and at the end of a contest, contesting software can help with submitting your log. <p> After you've done this for a while, you'll notice that contest rules and scoring change over time. That brings with it the possibility of your software using old and invalid rules for validation, scoring and other contesting requirements. <p> In most cases, software is updated manually by the author to implement the latest rules. This means that authors are required to keep up to date with the rules for all of the contests that their software supports, let alone add new contests. <p> There are a few applications that support the idea of a contest definition which suggests the ability for anyone to define contesting rules to use them within the application. Unfortunately their functionality is strictly limited and they are not sufficient to define every contest rule that is in use today. Sadly, flexible as they might seem, they're neither universal nor compatible with each other. One definition, written by one amateur, for one application, cannot be used anywhere else, never mind trying to determine what the latest version is. <p> I strongly believe that we need a shared open standard that can serve contest organisers, contest software developers and contest participants. Before I elaborate, I will be explicit in pointing out that the intent is to standardise in a way that makes it possible to document all past, current and future contests and in doing so, provide a collaborative way to share contesting rules between organisers, software developers and contesters, not to mention awards committees and amateur associations. <p> So, if such a contest rule standard were to exist, what would it look like? <p> Until now, the approach has been to create a list of keywords and values that deal with particular types of rules, things like band start and stop, zone score, valid prefixes, power level, exchange, etc. The result is a growing but always incomplete list of keywords with no means to define any logic. At the moment, all the contesting applications manage any scoring logic internally, requiring that it's updated when any of the rules change. Not only that, the contest organiser has no insight into the mechanism and no means to validate the process. <p> As a contest organiser, scoring hundreds if not thousands of logs is a whole different challenge. Many contests do this manually, rely on someone else's software, or if the contest is popular enough, write their own code to manage the process. <p> All this effort creates a disconnect between the contester, the organiser and the contest software developers, each using their own definition of the rules of any particular contest. <p> A different approach might be to implement specific rules in a universal programming language like say JavaScript, and use those to manage the scoring and validation logic specific to each contest. <p> For example, you might define a function that returns the starting and ending time for a contest which gives you a mechanism to detect if the contest is happening right now. A contester could use it to determine when the contest starts and ends, but the same definition could be used by the organiser to determine if a submitted log entry is for a valid time. <p> Another might be a function that uses a callsign to determine if it attracts points or not and if it does, how many. Contesting software might use it to change the colour of the screen to indicate an invalid entry, but an organiser might use it to exclude a contact from a log. <p> You could have a function to determine if the exchange is valid, or what the next exchange number is, or if the frequency on which the radio is currently tuned to is allowed for a contest. <p> You could combine some of these simple rules to determine, for example, if the frequency the radio is on is the same or different since the last contact and if that's permitted or not within the rules. <p> As long as the framework in which this standard is defined is extensible, any contest could be defined in this way. <p> If it's written well, contest organisers might be able to write their own rules using this standard and everyone can use the same rules for their own needs. <p> You might recall that I've spoken about aspects of this problem before and at the time I suggested that an amateur radio standards body would be helpful. Failing that there's nothing stopping a few people collaborating in a discussion about how this might be implemented. <p> As an IT professional outside my shack I have some ideas on what's needed and what could give the whole amateur community something useful, but unsurprisingly, I don't know everything. Working together as contesters we might come up with a better result. As a starting point, I've created a repository on GitHub called "amateur-contesting-standard" to start a conversation about this scheme and I would love to read your thoughts and see your ideas on how this might be achieved. <p> If you'd like to get in touch, send an email to cq@vk6flab.com or find my callsign on Twitter and GitHub. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

If you had money, what would your amateur adventure look like?
Foundations of Amateur Radio <p> A couple of weeks ago a friend, Ben VK6NCB asked an interesting question in our weekly net. He wanted to know, if money wasn't a concern, what would your ideal shack look like? The answers varied widely from leaving everything as is and using the money to retire, through to purpose built fixed or mobile shacks, with world wide DXCC activation travel and everything in between. <p> My own answer was a little different. I envisaged establishing an RF research laboratory and spending my life exploring and investigating the ins and outs of the fundamentals of our hobby. Building software defined radios and building tools to leverage their capabilities. <p> As far-fetched as money not being a concern might sound, it's something that a group of radio amateurs had to grapple with in 2019 when their group came into some money. The result is a private foundation with the aim to support, promote, and enhance amateur radio digital communications and broader communication. <p> The foundation, Amateur Radio Digital Communications or ARDC uses its resources to provide grants to the amateur community. There's a number of criteria to be eligible to receive an ARDC grant, but you must at least relate to the support and growth of amateur radio, education, research and development. Grants are evaluated on a range of aspirational goals, things like reach, inclusiveness, innovation, social good and others. <p> One of the first questions you might ask is how did these people get the money and why are they giving it away? <p> To answer that we'll need to travel back to 1981 when Hank, KA6M had the foresight to imagine that Internet-style networking was going to be a thing and requested a block of IP addresses for use by radio amateurs. If you're not familiar, an IP address is like a telephone number, but for a computer. Hank was granted a block of 16.7 million addresses. For decades these were informally administered by a group of volunteers working under the name of AMPRnet and later 44Net. <p> In 2011 the group founded ARDC as a California non-profit and officially took ownership of the network space and its management. <p> At this point I'll make a slight detour into IP addresses. I promise it's relevant. <p> For information to travel to a computer on the Internet it needs to have an address. That address, originally specified using a 32-bit number, a so-called IPv4 address, made it possible to uniquely identify around 4 billion computers. With the explosive growth of computing and the Internet, the world started running out of addresses and in 1998, IPv6 was proposed to solve the problem. It uses a 128-bit number and has space to uniquely identify something like 340 trillion computers. <p> In 2018, the ARDC was presented with a unique opportunity to sell some of its increasingly valuable address space, due to IPv4 address scarcity, but soon to be worthless, due to IPv6 adoption. After a year of internal discussion, in the middle of 2019, the decision was finalised and the ARDC sold a quarter of the address block that Hank had been granted back in 1981. On the 18th of July, 2019, Amazon Web Services became the proud new owner of just over 4 million new IP addresses. <p> I should point out that radio amateurs haven't ever used more than half of the original block and IPv6 is going to make this no longer any issue. <p> So, how much did they make from this adventure? <p> Well, each address sold for about $25, making for a lump sum of well over $100 million dollars which the ARDC used to establish its grants program. To round off the story, in 2020, the ARDC changed from a public charity to a private foundation and continues to administer the 44Net and the grants program. <p> Their grants list is impressive and inspirational, so check it out on the ampr.org website. While you're there, you can subscribe to the newsletter and read about some of the amazing work that's flowing from the ARDC as a result of its efforts. <p> At this point you might be getting all excited about applying for a grant and you should, but I'd like to ask a different question. <p> What have you done lately to grow our hobby, to stimulate it, to encourage new people, to innovate, research and learn? What has been your contribution? <p> So, if you had money, what would you do with your amateur adventure? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How to isolate and by how much?
Foundations of Amateur Radio <p> If you connect the antenna ports of two radios together and transmit from one into the other, that would be bad, right? Just how bad would it be and what could you do differently? <p> Before I dig in, you might ask yourself why on Earth this question even arises. <p> Consider having two radios and one antenna. You couldn't use a T-piece to connect two radios to the antenna unless both were receivers. So, after connecting and disconnecting coax for a decade, you might decide to use a two position coaxial switch instead. Set the switch to one port and the first radio is connected to the antenna, flick it to the other port and you've just avoided swapping coax between radios. <p> I'll point out that in most cases a coaxial switch can be used to connect multiple antennas to one radio, or in reverse, connect multiple radios to one antenna. <p> When you do start looking for a switch it would be good to test that at no point it connected any two switching ports together, potentially causing the magic smoke to escape from your radio. <p> A less obvious issue is that a coaxial switch has a property called isolation. It's a measure of what part of a signal leaks between ports and you'll see the isolation or cross-talk of a switch described in decibels or dB. <p> If you recall, a dB is a relative measure. It means that it's something in comparison with something else, in our case, the amount of signal going into one port compared with the amount of signal leaking through to a disconnected port. <p> You'd think that in a perfect switch none of the signal would leak through, but it turns out that under different frequencies a switch responds differently, even one specifically designed for switching radio frequencies. It might be that a 1 kHz signal is completely isolated, but a 1 GHz signal is not, which is why when you look at the specifications of a coax switch, you'll see something like "greater than 70 dB isolation at 200 MHz". It's worth noting that the lower the frequency, the higher the isolation, indicating that in the worst case, at 200 MHz, there's 70 dB isolation, but at lower frequencies it has higher isolation, sometimes much higher. <p> If you were to transmit into this switch with 5 Watts at 200 MHz, the amount of signal that can leak through would be 70 dB less than 5 Watts. <p> You might recall that you can convert Watts to dBm to allow you to do some interesting calculations. As with other dB scales, it's in comparison to something else, in this case a dBm is in reference to 1 milliwatt and 5 Watts is the equivalent of 37 dBm. This means that if you had a switch with 70 dB isolation, you'd start with a 37 dBm transmission, take 70 dB isolation and end up with a -33 dBm signal leaking through. That's the same as 0.0005 milliwatts. In other words your 5 Watt transmission leaks through your coax switch to the tune of 0.0005 milliwatts. <p> Is that enough to damage your radio? <p> Well, that depends on the radio, but let's put some numbers against it. <p> S9 on VHF and UHF was defined in 1981 as -93 dBm assuming a 50 Ohm impedance of your radio. <p> So, our leaking signal, -33 dBm, is 60 dB higher than S9. You'd report it as a 60 over 9 contact, a tad excessive, but not unheard of. So by that metric, you should be fine. <p> Many, but not all, radios specify the maximum radio frequency or RF power that they can handle. For example, according to the documentation, both the NanoVNA and a Icom IC-706 can each handle a 20 dBm or 200 milliwatt signal without doing damage. That means that your -33 dBm signal should't do any damage to those two devices. <p> I'm off to see what the isolation is for cheap 12V relays to see if I can construct a cost effective, modular, remote control antenna switch with lightning detection. <p> What are you building next? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Smith, the chart to end all charts ...
Foundations of Amateur Radio <p> In the time that I've been a radio amateur not a day has gone by without learning something new. Today was no different and this time learning took me both by surprise and delight. I realise that being delighted by charts, since that's what we're talking about, might not be something that comes naturally, but I can highly recommend that you use this as an opportunity to explore. <p> So, which specific chart am I referring to? <p> The venerable Smith Chart, something which I've seen from a distance many times in the past decade, but never actually understood, or to be honest, even looked at with anything more than a glance and a shudder. <p> My first exploration started with a book published in 1969 by the person who developed the chart, Phillip Hagar Smith, an electronics engineer. The book, over 250 pages, is dense and frankly my reading of the first part of the book did not fill me with delight, but based on what I discovered afterwards, I might revisit it. <p> The purpose of the Smith chart is to visualise complex mathematical relationships. Instead of filling your worksheet with a litany of calculations, you can draw lines, circles and read the answer straight off the chart. <p> For example, given the impedance of an antenna system, determining the standing wave ratio becomes a case of putting a dot on a chart, drawing a circle through the dot and reading the VSWR straight off the chart. <p> It gets better. <p> If you have a digital Smith chart, like the one shown on a NanoVNA or a RigExpert antenna analyser, you can read the antenna impedance in relation to frequency, use a tuner to change it and see the chart update in real-time in direct response to you changing inductance or capacitance by twiddling the knobs on the tuner. <p> One of the main things that a Smith chart solves is to visualise a chart with infinity on it, twice. In radio a short-circuit is one extreme and an open-circuit is another. Coming up with a way to show both those conditions on the same chart is a stroke of genius. <p> The chart has evolved over time, but in essence it's a circle with an amazing set of arcs drawn throughout. The very centre of the chart has the number 1.0 next to it. That's the point at which the VSWR is 1:1, the reactance is zero and it's called the prime centre. A dummy load should show up as a dot in that spot, regardless of frequency. <p> The Smith chart is normalised. It doesn't matter if you're using a 50 Ohm or a 75 Ohm antenna network system, the middle of the chart is 1.0. Follow the horizontal axis to the right and you'll discover 2.0, that represents twice the resistance. If you're using a 50 Ohm system, 2.0 represents twice that, or 100 Ohm. Go to the left, find 0.5 and that represents half, or 25 Ohm. The far left point on the horizontal axis represents zero Ohm, or a short circuit, the far right represents infinite resistance, or an open circuit. <p> Positive reactance, or inductance is shown above the horizontal line, negative reactance, or capacitance is shown below the line. <p> Going back to the middle of the chart, you'll discover a circle. All along that circle the resistance is the same, that is, on a 50 Ohm system, all of that circle represents 50 Ohm. If you look directly above the prime centre, you'll discover another 1.0 on the edge of the chart. The arc coming from that point represents an inductive reactance of 50 Ohm all along its path. Similarly, at the bottom of the chart you'll see an arc coming from a 1.0, representing the capacitive reactance. <p> Before you pack it in with all this inductive and capacitive reactance, think of it as another attribute of your 50 Ohm antenna system. You don't need to precisely know how it works in order to use it. <p> Remember how I mentioned that you could just read off the VSWR from the chart? <p> Drop a point on the chart, anywhere is fine. You can read off both the resistance and reactance following the two arcs through that point. If you draw a circle through the same point with the centre at the middle of the chart, the VSWR of that system is the number that you can read, where your circle crosses the horizontal axis. <p> Before I go, there are plenty of YouTube videos on the topic, but there are a few that I'd recommend you explore. Among an amazing array of RF educational videos, Rhode and Schwartz made a ten minute presentation called "Understanding the Smith Chart" which walks you through how to read the chart and you don't need the prerequisites to follow along. In Part two of his "Smith Chart Basics" series, Carl Oliver shows how to look up the VSWR in three easy steps and Alan W2AEW has several videos showing the chart in action with several vector network analysers or VNAs and I'd recommend that you look at videos 264 and 314 to get started, but there's plenty more of his handy work to explore. <p> If you take away anything from this, it should be that the Smith Chart isn't scary, there's just lots of stuff there, but spend a few minutes looking at it and you'll discover just how useful it can be in your day to day amateur antenna tuning adventures. <p> If you've come across other interesting resources on the topic, don't hesitate to get in touch. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Can you build an all HF band concurrent WSPR transmitter?
Foundations of Amateur Radio <p> It is in my nature to ask questions. It's been hammered into me from an early age and it often brings me new friends, new ideas and new projects. After spending quite some time mulling over my understanding of radio, I came up with this question: "Is it possible to build a single radio transmitter that is capable of emitting a WSPR signal at the same time on all the HF bands?" <p> Before we look at the hardware, let's contemplate for a moment what this transmission might look like. <p> Imagine a WSPR transmission as a normal audio signal. It sounds like a couple of warbling tones for two minutes. Unpacking it, the audio signal is about 6 Hz wide and sits somewhere between 1400 and 1600 Hz. If you were to draw a power chart of this, displaying the frequencies horizontally and power vertically, you'd see a completely flat chart with a little spike, 6 Hz wide, somewhere between 1400 and 1600 Hz. <p> Using an analogue radio, you can play this sound into the microphone or audio port and the radio takes care of transmitting it on the 10m band as a 28 MHz beacon. Tune the radio to 40m and it appears as a 7 MHz transmission. <p> The two takeaways are that the WSPR signal itself doesn't change between bands or transmissions and the radio does the heavy lifting to make your WSPR transmission come out at the right frequency. <p> Your radio is moving the audio frequencies to the correct amateur band. The electronics in your radio achieve this move by mixing the audio and the tuning frequencies together. <p> If you imagine a 28 MHz WSPR signal coming from your transmitter as a power chart, it's essentially silence, except for a little WSPR peak somewhere just off to the right of 28 MHz. <p> From a mathematical perspective, the frequency mixer in your radio is performing a multiplication and best of all, you don't need a radio to do this. You could use software to multiply frequencies instead and end up with something that represented their product. If you were to create a power chart of this equivalent multiplication, you'd see a completely flat chart with a little spike near 28.1261 MHz. <p> Sound familiar? <p> It gets better. <p> You can store the result of this calculation in a file as a 28 MHz WSPR signal and you could do this as many times as you want. You could create a file with a 3.5 MHz WSPR signal, one with a 7 MHz one and so-on. <p> Since we're talking about shuffling numbers only, you could combine all these calculations, and end up with a single file that had several WSPR signals inside it. <p> The chart picture is again mostly silence, just with little WSPR peaks at frequencies suitable for say transmission on the 80, 40, 15 and 10m bands. <p> Now all you need is to find a device that's capable of transmitting it. <p> Turns out that we have such a device. A PlutoSDR, a software defined radio which I've spoken about before. It's capable of transmitting a 56 MHz wide signal, more than ample for what we're doing. We don't need to use the PlutoSDR to calculate the combined signal either, since we can do all that in advance, because as I said, a WSPR signal doesn't change. <p> So essentially, all we'd need to do is generate a file that has all the WSPR signal information at the right frequencies and send it to the PlutoSDR to transmit. <p> There are a couple of hurdles to overcome. <p> When you multiply two frequencies, you end up with two peaks, one at the sum of both frequencies, and one at the difference between them. One you need, the other you don't, so we're going to need to filter this out, something that your analogue radio circuit also does. <p> Another challenge is around sampling rates. The PlutoSDR needs a specific sampling rate and bit depth, so we're going to have to generate our file just so. I'm going to skip past complex numbers and move on to power output, since all the power from the transmitter will be spread across all of the combined WSPR signals we're attempting to transmit, so we're likely going to need amplification. <p> There's also the matter of testing before we actually connect this contraption to an antenna and I've glossed over one minor but essential point, the PlutoSDR doesn't do HF. <p> So, where does this leave us? <p> We can build a proof of concept using 2m and 70cm. Both those bands are native to the PlutoSDR. I'm currently working on generating the actual WSPR signal file to start the transformation process. A friend has some testing gear that could allow us to see what's coming out of the transmitter without polluting the airwaves and of course, at this point this is all still "What-if". I've not actually made this work, but it's keeping me entertained and that's half the fun. <p> It gets even better. The Pluto has an FPGA on board, so theoretically at least, we might be able to generate this actual file inside the Pluto in real-time, which opens up a whole other avenue of exploration, but we'll start with crawling before running. <p> If you have thoughts on this, or any other aspect of the hobby, please get in touch. You can send email to cq@vk6flab.com or you can find me on Twitter and Reddit with my callsign. <p> In the meantime, you know the drill. Get on air and make some noise. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What are the rules for calling CQ on a repeater?
Foundations of Amateur Radio <p> When you finally get to the point of pushing the talk button on your microphone, after passing the test, receiving your license, getting your radio, building an antenna, digesting the manual, identifying a repeater, untangling its offset, programming those frequencies and keying up, you might be surprised to realise that you're lost for words. Something which I've talked about before. <p> Even if you do have something to say, finding a person to say it to will be the next big challenge. Truth be told, the more frequencies you have to choose from, the harder it seems to discover a fellow amateur and with Internet connected repeater networks, your choice appears infinite. <p> So, how do you initiate communication on a repeater? Do you call CQ, ask for a signal check, or just kerplunk the repeater to prove that your signal is getting in? <p> The very first thing to remember is that you have the exact same rights as every other amateur. No amateur is above any other, though hearing some conversations or responses might give you a different impression. <p> Before you embark on a long speech, what you need to remember is that your ability to receive is not usually the same as your ability to transmit. If you're using a low-powered hand held radio that's tuned to a local repeater, you might be comparing your little stubby antenna, inside your home, held at an angle, with that of a high power repeater, with a high-gain antenna bolted to a tower installed on the top of a hill. In other words, you can hear the repeater much better than it can hear you. <p> You'll quickly observe that there are amateurs about who have their radio on all day long and they'll often hear every single transmission that hits the local repeater and even random frequencies. Sometimes this means that you'll have a great friend to talk to, other times it means that you'll have a local troll who in their not so humble opinion determines what is permitted and what's not. <p> So, to get things rolling, you should follow the KISS principle, an aim championed by the lead engineer of the Lockheed Skunk Works in 1960, Kelly Johnson, "Keep it simple stupid.". <p> With keeping things simple, there is a fierce and ongoing debate around the use of the phonetic alphabet on a repeater. With the benefit of experience, having run a weekly radio net for over a decade I'm going to be blunt. When you're identifying yourself to the rest of the community, always use phonetics. Only if you've been acknowledged and you're part of the conversation should you even consider dropping your phonetic callsign. <p> The reason is that your first transmissions will be regularly interrupted by others since they're having a conversation and you'll be butting in. Even if a net controller asks for check-ins, you should use phonetics, since you might not be the only one who keys up at the same time. If you and the controller have known each other for years and they recognise your voice, you could consider dropping the phonetics, but don't expect everyone to know who you are from a single letter getting through. Some people are better at this than others. <p> Whatever you do, don't barge in with a whole story until you've been acknowledged and the microphone has been handed to you. After all, this is a public shared space. <p> The next thing to consider is the audience you're talking to. If the repeater is just local, then the people within range are likely to expect your prefix and know who you are, so just your call might suffice, but if you connect to a network, that's not likely to be true. If you want to actually talk to anyone, you can call CQ, but if you just want to let people know you're there, you can say your callsign followed by the word "listening". <p> If you want to speak with a specific individual on the other hand, you can call them using their phonetic callsign, either with or without the CQ. Also consider they might be on the other side of their shack working hard at attempts to avoid sniffing solder fumes and take a moment to get to the microphone. <p> In other words, what you say on your repeater depends on what result you want and who else is there. Sometimes there will be a mismatch between the two, just saying your callsign might initiate an hour long conversation, and calling CQ might give you the local troll telling you to go away. <p> Don't let that dissuade you. Even with years of practice, sometimes the results are unexpected. <p> Talking on a repeater is like being invited to a party. There are going to be people you know, people you want to know and people you never want to meet again. <p> So, be considerate, listen more than you talk and be deliberate in your intentions and you'll be fine. <p> Thanks to Sandip EI7IJB for the question, "What are the rules for calling CQ on a repeater?" If you have other burning questions, get in touch and ask. I'll try to give you a coherent answer. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The Thunder and Lightning that destroyed my station ...
Foundations of Amateur Radio <p> The other day I was woken by the sound of a thunderclap. It was shockingly loud and came out of the blue. A few moments later, it happened again. I exploded out of bed, rushed to the shack, disconnected the beacon power and switched the antenna coax to "safe". <p> After breathing a sigh of relief, everything went dark and with it came the distinctive sound of the sudden death of the uninterrupted power supply taking with it my workstation. <p> With nothing else left to do, I reported the outage to the power company, went back to bed, pulled the covers over my head, snuggled in and surprisingly, slept pretty well despite the barrage of water hitting my QTH. The next morning the power was back on and I discovered that one of the residual current devices, the one that powered most, if not all, the wall sockets had tripped. I reset it and much to my surprise, most of my QTH came back to life. <p> I say most, because after breakfast I had a moment to switch on my radios and see what, if any, damage there was. I could hear and trigger the local repeater, but HF was strangely dead. I could hear the coax switches turning on and off, but the SWR on the antenna was high and it didn't appear that the antenna coupler was doing anything. It's powered remotely using a device called a Bias-T. You use two of them to transport a power supply voltage along your antenna coax. In my case, I inject 12 Volts in my shack, and extract the 12 Volts at the other end near the antenna where it powers the antenna coupler. <p> Occasionally the antenna coupler needs a reset, so I removed the power, waited a bit and reconnected. Still no response from the coupler, so I disconnected the power and left it for another time. <p> A few days later I had a moment to investigate further, so I went outside to check out the antenna and coupler. Both looked fine. I removed and reinserted the power, heard a click, but wasn't sure since a car came barrelling down the road at the same time, so tried again and heard nothing. <p> At this point I decided that this warranted a full investigation and started putting together a mental list of things I'd need. I wanted to test the coupler when it was isolated, I wanted to do a time-domain-reflectometry, or TDR test, to see if anything had changed. This test uses the RF reflection of a cable to determine its overall length and any faults like a cable break, high or low resistance and any joints. If you have a Nano VNA or an antenna analyser, you can do this test. It did occur to me that I didn't have a baseline to compare with, so that was disappointing, but I added it to the list. <p> First thing to test was to check if the radio had been affected. I turned it on, did the same tests and discovered that the Bias-T was still disconnected, which could explain why I didn't hear a click when I tested a second time. Armed with a level of confidence around power, I tried again to trigger the antenna coupler and got nothing, dread building over the potential loss of a radio in the storm, I set about swapping my HF antenna to another radio. <p> At this point I was reminded of an incident, 37 years ago, as a high school student during a class outing. My wonderful and inspirational physics teacher, Bart Vrijdaghs, took us to the local University where the head of the Physics Department of the University of Leiden gave us a tour of their facilities. He took us into a student lab full of oscilloscopes and tone generators and set-up a demonstration to show us how you could generate Lissajous figures. He was having some trouble making it work and with the impertinence reserved for teenagers I quoted a then popular IBM advertisement from 1985, "Of Je Stopt de Stekker Er In", which loosely translates to asking if he had plugged it in. <p> I can tell you, if looks could kill, I wouldn't be telling this story. <p> Suffice to say, it wasn't. Plugged in, that is. <p> Back to my HF antenna. <p> Yeah. It was already plugged into the other radio, so, unsurprisingly it was unable to send any RF to, or from, the first radio, much like some of the advanced telepathic printers I've had the pleasure of fixing during my help desk days a quarter of a century ago. <p> After all that, I can tell you that HF seems to work as expected. The beacon is back online and I have some work ahead of me to create some baseline TDR plots and perhaps a check-in, check-out board to keep track of what's plugged in where. <p> That and looking for another UPS, since keeping the computer it's connected to up and running, at least long enough to properly shut down, would be good. <p> What other lessons can you take away from lightning hitting nearby? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

When should I go on air?
Foundations of Amateur Radio <p> When you obtain your license there's a whole lot of learning to be had before you even get started with your first transmission, but when you get there you'll discover that learning has just begun and the rest of your life will be beset with challenges, quests, discovery and dawning understanding. <p> One of the early and recurring questions is around the best time to be on air. Before I get into the why, the answer is, right now. <p> This interminable question will continue to haunt you throughout your life, and the most pressing answer will be shaped around the missed opportunity. You'll discover tools that assist with predicting propagation, web-sites that explain what the various layers of the ionosphere do and how they affect your ability to use radio to make contact with other amateurs. <p> There's learned discussion around testing and tracking propagation, special modes that help create your own maps for your own station and you'll discover an endless supply of experts who will advise you when you should power up your transceiver and call CQ. <p> Whilst I've only been an amateur for a short time. In the decade to date I've learnt one thing about propagation. Despite all the tools, the discussion, the maps and forecasts, there is no substitute for actually getting on air and making noise. Over the past while I've been watching the propagation from my own shack using a 200 milliwatt beacon and I've discovered that running 24 hours a day, every day, well, almost every day, my signal gets to places far beyond my wildest dreams. <p> I have also discovered trends. That is, the average distance of the signal reports is increasing over time. This isn't a linear thing, not even a recurring thing, much like the ebb and flow of the tides, varying from day to day, a little bit at a time, inexorably making your shoes wet when you least expect it. <p> While to some extent we've tamed the prediction of the tides with complex and interrelated cycles, discovered by using Fourier transforms, we're no-where near achieving this level of sophistication for the ionosphere and its associated propagation. <p> Just like predicting a specific wave is still beyond the capabilities of a tide table, predicting the ability of a radio wave to make it from your antenna to that of another amateur is beyond any tool we have today. <p> Another way to look at predicting the complexity associated with the ionosphere is comparing it to weather forecasting. We have national forecasting bodies, with millions of sensors, super computing cycles that dwarf most other research, a global network of satellite sensors, roughly a quarter of which have some form of earth sensing capability, transmitting terrabytes of data every day and still we cannot determine where on Earth it's going to rain tomorrow. <p> The ionosphere, whilst it's being monitored, is not nearly as well resourced. It's not nearly as visible to the average person as the packing of an umbrella and the political perception of need is nowehere near as urgent as getting the weather right. <p> So, absent accurate forecasting, finding a better way to determine when to get on air is required. That said, I've discovered that regret is the biggest motivator to get on air. The day after a contest when a friend made a contact with an amazing station, or the lunch break where I didn't power the radio on to discover a random opening to a clamouring horde of calls looking to make contact. <p> So, my best advice to you is to get on air whenever you can. You might not make a contact every time, but you'll discover what the bands look like right now and you'll have the chance of hitting the jackpot with a rare contact and truth be told, I think your chances of making a contact are higher than winning the lottery. <p> When you do take that step, you'll start discovering the ebb and flow of the bands, discover the characteristic sound that each band makes and what a band sounds like when it's open and when it's not. You'll hear stations far and wide, discover that while there are trends in propagation, there are no rules. From one moment to the next, you'll discover the thrill of hearing something unexpected. <p> One thing to consider, if you get on air for the sole purpose to make contacts, you're likely going to be disappointed. It's like fishing. Most people don't get up at some crazy hour, sit on a damp jetty, freezing parts of their anatomy off for the sole purpose of catching fish. <p> So, get on air and make some noise, today. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Augustin-Jean Fresnel, Zeppelins and a picket fence ...
Foundations of Amateur Radio <p> In our hobby we regularly invoke line of sight when we discuss the VHF and higher bands. It's a simple concept to help describe when two transceivers can hear each other. The process evokes an image of a beam of light travelling unobstructed between the antennas at either end. Some might picture a laser, others a flashlight, both are useful to become familiar with some of the concepts. <p> If there's a pole between the two, a laser beam, unless it's particularly powerful, won't go through to the other side. A flashlight beam on the other hand might fit around the pole and still be visible at the destination. That illustrates that objects can get in the way of a signal, reducing strength and sometimes blocking it entirely, but it's not the only effect at play. <p> Imagine a building with a mirror glued to its side. If you shine a laser at an angle at the mirror, you can reflect the light off the mirror and essentially still land on target. This is useful if you want to avoid an obstacle directly between you and your destination. <p> The reflected light travels a different and slightly longer distance than direct light would, but if there's no obstacles, both will arrive at the destination. <p> This is an example of a multipath, where the same signal arrives at its destination using multiple different paths. <p> If you've ever used HF radio, making a contact on the other side of the planet, it should come as no surprise that radio waves travel in more than just straight lines. Depending on frequency, radio waves can be affected by phenomena like ionospheric reflection and refraction, atmospheric ducting and even bounce off water, the ground, mountains, hills and objects like buildings, aircraft and even water droplets, along their path. <p> Each of these cause a radio signal to take multiple paths to arrive at the destination. <p> It gets better. <p> A radio signal that travels along a different path takes a measurable difference in time to get to its destination when compared with another path for the same signal. From a radio signal perspective, this difference in time is also known as a phase shift. <p> Now consider a single radio signal that travels along two paths, just like our laser beam and mirror. If you imagine a radio signal as a sine wave, you can draw the two signals on the same chart. They will be in lock-step with each other, since they're the same radio signal, but they won't be on the same place on the chart. In relation to each other they'll be shifted along the time axis, since one took longer than the other to get to the destination. <p> At the destination, the receiver hears a combination of both those signals. They're added together. That means that what's sent and what's received are not the same thing and why it's a great idea to use phonetics in radio communications. In some cases the two signals help and strengthen each other, they're said to interfere constructively, and sometimes the signals hinder and cancel each other out, or interfere destructively. <p> Said in another way, a radio signal can arrive at a receiver along multiple paths at the same time. What's heard at the receiver is essentially a cacophony, caused by each slightly different path. Since the signals are essentially all the same, some of these signals reinforce each other, where some cancel each other out. <p> This effect isn't absolute, since the different path lengths aren't all exact multiples of the wavelength of the signal, they're all over the place, but there will be groups of paths that help and groups that hinder. This phenomenon was first described by Augustin-Jean Fresnel on the 14th of July, 1816 in relation to light and we now call these groups, Fresnel zones. <p> Fresnel zones are numbered, one, two, three and up. The first or primary Fresnel zone is the first group of radio signals that helps strengthen the signal, the second zone is the first group of signals that hinders. The third zone is the second group of radio signals that helps and so-on. Odd helps, even hinders. <p> I should point out that a Fresnel zone is three dimensional. The primary Fresnel zone essentially has the shape of a Zeppelin stretched between the source and the target. The secondary zone is wrapped around the outside of the primary zone like a second skin, but it's thicker in the middle. <p> In practical terms, what this means in point-to-point radio communications is that your antenna needs to be located in a place where most of the signal arrives. The rule of thumb is that the primary Fresnel zone needs to be at least 60% clear, but ideally 80%. <p> If you're in a situation where a receiver is moving, say in a car, you can imagine that your antenna is moving in and out of direct line of sight to a transmitter, but it's also moving between the various Fresnel zones. If you were to move your antenna from the first Fresnel zone to the second and then the third, the signal would be strong, then weak, then strong again. <p> If your receiver is an FM receiver and it's moving from the first zone to the second, it could fall below a threshold and the signal would effectively vanish. Continue to move from the second into the third zone and the signal would sound like it suddenly reappeared as it climbed above the threshold. Do it fast enough and the signal sounds like it's stuttering. <p> That stuttering has a name. In amateur radio we call it picket fencing or flutter and it's commonly heard in mobile situations on FM transmissions on the VHF and higher bands, but it can be caused by other changes in propagation distance, for example an antenna moving in the wind. The higher the frequency, the less movement is needed to experience this. <p> To add to the fun of radio, the same threshold effects, actually called the FM capture effect, can be caused by other phenomena, like two stations of similar strength on the same frequency, or interference from the electronics in your vehicle. <p> And finally, I should point out that the higher the frequency, the smaller the Fresnel zones, and the more susceptible to an object in the path a signal is, but you already knew that, a pole will block a laser beam, but not a 2m conversation on the local repeater. <p> So, line-of-sight isn't just a straight line, it's a whole lot more fun. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The Science of Amateur Radio
Foundations of Amateur Radio <p> The amateur radio community is as varied as humanity across the globe. It represents an endless supply of ideas and experiments that continue to attract people looking for something new and exiting. <p> On the face of it, our hobby is about radio and electronics, about propagation and antennas, about modes and contacts, but if you limit your outlook to those topics you'll miss out on a vast expanse of opportunity that is only just beginning to emerge. <p> Until quite recently, computing in amateur radio was essentially limited to logging and contest scoring. It has evolved to include digital modes like PSK31 and the advent of smaller, faster and cheaper computers in the home has brought the possibility of processing unimaginable amounts of data leading to modes like WSPR and FT8. <p> In the past I've spoken about how amateur radio means different things to different people. Making contact using a digital internet enabled repeater is sacrileges to one and manna from heaven to another. Between those two extremes there is room to move and explore. Similarly where one uses valves, another expects an integrated circuit. One wants low power, the other wants every Watt they can lay their hands on. Contesting versus rag chewing, nets vs contacts, SSB vs. CW, FT8 vs. RTTY. Each of these attracts a different part of the community with different outcomes and expectations. For some it's about antenna building, others going portable, climbing a mountain, or setting up in a park. <p> Those are all traditional amateur activities, but the choice and opportunity don't end there. <p> The longer I play with computers the more I see a convergence in the world, a coming together of technologies and techniques. I've talked about some of this before when in 1994 I produced a competition broadcast promotion for the radio station I was working at, using just a computer in the era of reel-to-reel tape and razor blades. My station manager couldn't quite put his finger on what was different, but with hindsight it represented a landslide change in how radio stations have operated since. Mind you, I'm not saying that I was the first, just the first in that particular radio station. <p> In many ways computing is an abstract effort. When asked, I like to express it as designing something intangible in an imaginary world using an made up language and getting paid real money to make it happen, well, numbers in my bank account at least. <p> Within that context, amateur radio is slowly beginning to reap the rewards that come from the exponential growth in home computing power. While the majority of humanity might use the vast amount of CPU cycles to scroll through cat videos online, that access to processing power allows us to do other things as well. <p> For example, right now I'm playing with the dataset that represents all the WSPR spots since March of 2008. As of now there are around four billion rows of contacts, containing data points like a time-stamp, the transmitter, the receiver, the signal strength, location, direction, and more. <p> As part of that investigation I went looking for documents containing the words "RStudio" and "maidenhead", so I could consider creating a map in my statistical tool that allowed me to represent my dataset. In making that search I discovered a thesis by a mathematician who was using the reverse beacon network in an attempt to predict which station could hear which transmitter at what time. <p> In reading the thesis, which I opened because I was looking for an example on how to convert a maidenhead locator into geo-spacial data types in R, a popular statistics platform, I discovered that the author didn't appear to have much, if any, amateur knowledge or experience, but they approached their task, attempting to predict as a mathematician what we in our community call propagation, based on a public dataset, downloaded straight from the reverse beacon network, created by amateurs like you and I. <p> This interaction between science and the amateur community isn't new. Sometimes it's driven by science, other times it's driven by amateur radio. There's a team exploring the ionospheric prediction models that we've used for decades, popularly referred to as VOACAP or Voice of America Coverage Analysis Program, based on multiple evolutions of empirical models of the ionosphere that were first developed in the 1960's, headed by both a scientist and an amateur, Chris KL3WX. <p> With the advent of WSPR and the associated data collection some experiments have started to compare the reality of propagation as logged by WSPR to the predicted propagation as modelled by VOACAP. One such experiment happened in 2018 where Chris and his team at HAARP, the High-Frequency Active Auroral Research Program, set out to make transmissions at specific times and frequencies, using the amateur community logging of WSPR spots to compare their transmissions to the predictions. <p> Interestingly they did not match. Just think about that for a moment. The tool we love and use all across our community, VOACAP, doesn't match the reality of propagation. <p> My own playing with WSPR data is driven by the very same thing that I use to be a better contester, a burning curiosity in all things. My VOACAP prediction experience has been poor to date. Setting up my own WSPR beacon is the first step in attempting to discover what my actual propagation looks like, but in doing so, it's also a possible contribution to the wider challenges of predicting propagation based on a dataset with four billion spots. One such approach might be to create an ionospheric prediction map based on actual data and compare that to the models as well as the published space weather maps and combining these efforts into a machine learning project which might give us the next generation of ionospheric prediction tools, but only time will tell. <p> No doubt I will have to learn more about statistics and machine learning than I expect, but then, that's half the fun. <p> So, next time you think of amateur radio as being limited to valves, transistors, soldering, antennas and rag chewing on HF, consider that there might be other aspects to this hobby that you have not yet considered. <p> What other research are you aware of that relates to amateur radio? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The art of troubleshooting the digital world.
Foundations of Amateur Radio <p> The lure of digital modes and the opportunities they bring are enough to tempt some amateurs to begin a journey into integrating their radio and computer to make a new world come to life. This isn't without pain or challenge, but the outcomes are so enticing that many embark on this adventure every day. <p> As a person who has made this trip it's heart warming to see the joy writ large on the face of an amateur who makes their first FT8 contact on a home brew wire dipole rigged together on a Sunday afternoon to take advantage of the latest opening on the 10m band. <p> On the flip side, it's heart breaking to see an amateur falter at the first hurdle, attempting to make their computer talk to their radio and giving up because it just won't work. At first this attitude bewildered me in a community of experimenters, but over time I've come to understand that sometimes an analogue approach isn't suited to the digital world. There isn't really a place where you can attach your multimeter and see why the serial connection isn't working, nor is there any universal document that can walk you through how to set things up. <p> So, for you, if you're in a place where you've all but given up, let me see if I can find words to encourage you to keep trying. I'll skip the propaganda about going digital and move straight to making it work. <p> This might come as a surprise, but in the digital world, things are built in complex layers of interdependence. Said in another way, using an analogy, to turn on a light you need flick a switch, which depends on power to the switch, which depends on power from the fuse box, which depends on power from the street, which depends on power from the substation and so-on. <p> If you flick the switch and the light stays off, you need to figure out which part of the chain failed. Did it fail at the bulb or at the substation? If the street is dark, do you need to check the fuse box or the bulb? That's not to say that either, or even both, can also be faulty, but there's no point in checking until the street has power. <p> From a fault finding perspective, the number of variables that you have control over, in the case of a light bulb not switching on, is strictly limited. You can control the bulb and the fuse and in most cases that's about it, the rest of the chain is outside your direct control. <p> In attempting to make a computer talk to a radio you can be forgiven in thinking that the level of complexity associated with such a trivial task is just as direct and straightforward. Unfortunately, you'd be wrong. It's not your fault. A popular slogan "Plug and Play" made people think that computers were easy to use and control. <p> The truth is a far darker reality. One of the hidden sources of frustration in the digital world is the extreme level of complexity. In our quest to standardise and simplify we have built a fragile Jenga tower of software that can collapse at any point. Most of the time this is completely invisible but that doesn't cause it to be any less real. Computers are simple, but only if you control the environment. And when I say control, I mean take ownership of each change. <p> Updating the operating system? Installing a new application? Adding a new peripheral? Changing location? All these things, innocuous as they might seem, can fundamentally alter the behaviour of your environment. <p> As an example, consider the location of your device. Let's say that you changed the location of your computer, either physically or via a preference. All of a sudden your Wi-Fi network stops working. The one that you used for years. Turns out that changing location changed the Wi-Fi driver to stop using a particular channel, not permitted in your new location. If you're curious, this happened to me last week. <p> The point being that troubleshooting is about controlling change in that fragile environment. <p> So, when you're trying to figure out how to make your serial connection work, you need to stop fiddling with everything all at once and change one thing at a time. Discovering the layers of dependency makes this difficult at times, but not impossible. <p> For example, a working serial connection requires that both ends are physically connected, speaking the same language at the same speed. That depends on the radio being correctly configured, but it also depends on the computer having the right drivers installed. It also depends on the software you're using being configured correctly to talk to the right serial device and the operating system giving your software permission to do so. It depends on the software using the right radio mode and it depends on the radio being switched on. <p> Now, imagine the serial connection "not working". <p> Do you check the radio mode before you check if the radio is turned on? <p> What about the physical connection? <p> When you're troubleshooting, you cannot just look at the error message on the screen and follow that path. You need to ensure that all the underlying things are working first. You don't check the bulb until there's light in the street. Same thing. No need to worry about the error until you've discovered that the radio is on, the cable connected correctly, the driver installed correctly, the speeds set right and the mode configured properly. If and only if that's all correct, then look at the error. <p> This becomes harder if it worked yesterday. What changed between then and now? Did your operating system do an update? Did your radio forget its settings? Did the cat jump on your desk and dislodge a cable overnight? Is there an earth fault that caused the serial connection to cease working? <p> Sometimes, despite your best efforts, you cannot find the problem. <p> At that point you need to take a step back and think about how to prove that something is working in the way that you think it is. Multimeter to a light bulb to check continuity - style. In the case of a serial connection, what can you use to test the link if your favourite tool doesn't work or stopped working suddenly? <p> I've said this before, but it bears repeating, since it's not obvious. <p> Troubleshooting is all about discovering and controlling change. <p> Pick one thing to test, prove that it's correct, then pick the next. Eventually you'll come across a "Duh" moment. Don't sweat it, we've all been there. Now do it again! <p> What's your best troubleshooting moment? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How far can you go?
Foundations of Amateur Radio <p> Antennas and propagation are the two single most discussed topics in our hobby, that and how an FT8 contact isn't real. Not a day goes by without some conversation about what antenna is the best one and by how much? In my opinion it's a futile effort made all the worse by so called experts explaining in undeniable gobbledegook, or sometimes even using science, just how any particular antenna is a compromise. <p> The truth is that most conductive materials radiate to more or lesser degree. Sometimes there is enough of that to make it outside your backyard into the antenna of a fellow hobbyist. To make a point, as is my wont, over the past months I've been conducting an experiment. It's the first in a series all related to antennas and propagation. As has been said, the difference between fiddling and science, is writing it down, so this is me writing it down. <p> I'm using the tools available to me to explore the various attributes of my station and how it affects what's possible. I will observe that this is within the dynamic nature of the environment, so the solar cycle, solar events, thunderstorms and noise are making an impact. No doubt I'll create a visualisation that links some of those extra variables, but for now I'm just noting that these external events affect what I'm doing. <p> You might recall that I took delivery of a WSPR beacon a few months ago. If you're unfamiliar, WSPR or Weak Signal Propagation Reporter, is a tool that allows a station to transmit a time synchronised signal on a specific frequency, so other stations can look for, and attempt to decode it. Think of it as a timed Morse code signal and you'll have a pretty close understanding of what it does. <p> The beacon I purchased was a 200 milliwatt, ZachTek 80To10 desktop transmitter, built by Harry, SM7PNV. It can operate on all the HF bands I'm licensed for and can run all day, every day. It's time-synchronised using a supplied GPS antenna and powered by a Micro USB cable. It's currently connected to my vertical antenna. <p> That vertical antenna is a homebrew helically wound whip, tuned for the 40m band, clamped to the side of my metal patio roof. It's fed by an SGC-237 antenna coupler which is held by magnets to the roof. A 75 Ohm, RG6 quad shield coax cable, about 20m long, left over from my satellite dish installation days, is connected via several adaptors and coax switches to the beacon. <p> This is not a fancy set-up by any stretch of the imagination, but it's my station and what I use to get on air to make noise and that's the whole point of this exercise. You might recall that one of the reasons I want to learn Morse is so I can hear an NCDXF beacon and know which one I'm hearing on my own station. In many ways, this is a different way to approach the same problem. <p> Said plainly, "How do I determine what propagation is like for me, right now, on my own gear?" <p> There are countless tools available, from the Voice of America VOACAP propagation prediction, through the graphs and charts on clublog.org to the Space Weather Services run by the Bureau of Meteorology in Australia. <p> All of these tools have one thing in common, they don't use your own gear. <p> Unsurprisingly, you're likely to wonder what it is that I can achieve with a mere 200 milliwatt transmitter and a vertical. Turns out, quite a lot. As of right now, my WSPR beacon has been heard multiple times over the past three months in the Canary Islands, over 15 thousand kilometres away. The Watts per Kilometre calculation puts that at over 76 thousand kilometres per Watt, not bad for a little amateur station located in the middle of a residential suburb. Did I mention that this was on the 10m band? <p> I was asked if I would put a pin in my DXCC map, tracking the countries for each of these WSPR reports and my answer to that is "No". This is not a contact, this is a propagation ping. I suppose that I could, if I really wanted to argue the point, which I don't, use a pin if I had a reciprocal report from the other station within a set period of time, but that's not why I'm doing this. The purpose of this exercise is to discover what my station is capable of, what propagation is like, how it changes over time, how uniform my radiation pattern is and how much of the globe can hear my signal. <p> One observation to make is that much of the West Coast of the United States is a similar distance away from me, but so far there are no reports from that continent. As a quick and dirty test, I'm using my Yaesu radio and 5 Watts for the next day to see if this is an edge case, or if there is something else going on. For example, my house has a peak metal roof, to the West of my antenna. Is it possible that it's affecting the radiation pattern, or is there something else going on, like the neighbour's house that sits to the East? <p> For all I know the noise floor in the Canary Islands is significantly better than anywhere in the USA, but only time will tell. <p> I've recently taken delivery of a multi-band vertical antenna which I'm planning to use to replace my current vertical. The main reason being that my antenna coupler cannot tune with 200 milliwatts and to do band-hopping I'd have to re-tune manually each time, not something that is sustainable 24 hours a day. <p> No doubt that change will bring other discoveries, but then, I'm keeping track. <p> The intent of all of this is that you can experiment with your own station, test ideas, trial a set-up, keep a log and discover new things that your station presents to you. Amateur Radio is never just about one thing, it's always a dozen different things, all at the same time. <p> What are you going to discover next? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

After the chaos ... building the ideal shack
Foundations of Amateur Radio <p> One of the first questions a new amateur asks is "Which radio should I buy?" It's a topic I've discussed at length and the answer "It depends." is unhelpful without doing more research, but after you've done the work, you'll be able to answer it for yourself. <p> A question that is just as important, but not asked nearly enough, frankly, I've not heard it in the decade I've been part of this community, is: "How should I build my shack?" The answer is just as useful, "It depends." <p> So, let's explore what precisely your shack design depends on. Let me start with pointing out that I'm not here to give you answers, you can watch hundreds of YouTube videos, read a gazillion web-pages and get no closer than discover how others have answered this question. It wasn't until recently that I understood that it was a question at all, but airing my frustration at the level of dysfunction of my shack unearthed it and in attempting to answer my own question, I started to explore the landscape. <p> As with choosing a first radio, one of the very first answers you need for yourself about the ideal shack is: "What do you want to use it for?" <p> That in and of itself is not enough. I had an answer for that, I want to operate my weekly net, I want to do casual HF contesting, have a beacon running and have space for experimentation. It wasn't until Ben VK6NCB suggested that I dedicate a single radio to the weekly net and the contesting and use the other for experimentation, that I discovered that this wasn't going to work for me. <p> I want to be able to use both my radios at the same time, in a so-called Single Operator Two Radio setup, or SO2R. This will allow me to extend the boundaries of my comfort zone and in doing so, will give me plenty of new things to learn. <p> So, the question: "What do you want to use your shack for?" is probably the single most important thing you need to discover. If you're like me, the obvious answer is: "Everything!", but reality soon sets in and you might start to create an actual list of things that you want to do. Prompted by Ben's suggestion, I was able to articulate for the very first time something that I didn't want to do. I didn't want to set a radio aside for experimentation. So when you're considering what you want to achieve, also think about what you don't want. <p> For example, I have no interest in using the 6 meter band at this time. Not because it's a bad band, far from it, it's because I'm not permitted to use it with my current license. Same for the 23 cm band. This means that I don't have to find ways of making my shack accommodate those two bands. My current license permits me access to precisely six bands and the station I'm building only needs to access those bands at the moment. That brings me to the next question for the ideal shack design. <p> "How long do you expect the layout to last?" <p> For example, are you going to build a new building for your shack, for the next 50 years, or is it something that's going to last for the weekend? Is your shack going to be moved, or is it something a little more permanent? Are you going to change your needs and should you incorporate some of that into your design, or are you perfectly happy with what you're doing today? You have to remember, this is your shack, not mine, not your friends, yours. It means that it needs to accommodate what you want. <p> The next question, boring as it might be, "How much money are you going to spend?" <p> Building a whole new shack out of a catalogue is perfectly fine, but you might discover that the gear you have today is ample to get your shack started. You might leave space for a different piece of kit, or you might decide that the shack needs changing when a new shiny piece of equipment arrives in a nondescript brown box. <p> Some other things to consider are, "What operating actually looks like?" <p> I've seen shack videos that look like a tour through a radio museum with more radios than I have keys on my keyboard, sometimes all connected, other times, just stored on shelves to look at. <p> Are you going to have more than one radio operating at the same time and if so, how are you planning to control them? How many antennas are connected to this shack and how do you track which antenna is connected to which radio? <p> What are you going to do about power? Does everything run on mains power, or are you going to build a 13.8 Volt supply for all your gear? <p> Where are you planning to put computer screens, what about keyboard, mouse, Morse key and antenna switching controls? In other words, "What do the ergonomics of your shack look like?" <p> Remember, there is no right answer. The answer you come up with is yours and yours alone. Look at things that work for you and take note of things that make you wince when you see it in another shack somewhere. That's not to say that you should be dismissive, rather, use the opportunity to ask the shack owner why they made that choice. Who knows, it might cover something you hadn't considered yet. <p> So, what does your ideal shack look like? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

In the beginning there was chaos...
Foundations of Amateur Radio <p> Over the weekend I learnt to my chagrin that my shack was not ready for the contest I decided to participate in for an hour. Truth be told, it was probably me who wasn't ready, but I'm going to blame my shack, since it can't argue and besides this is my story. <p> It started off with turning on the HF radio. That involved turning off my 10m WSPR beacon which is transmitting its little heart out 24 hours a day into the one vertical antenna it shares with my HF radio. <p> Turning off the beacon was simple enough, reach into the mass of cable and dig out the USB power lead that plugs into the beacon. Then follow the antenna coax to the correct switch. Whoops, that's the GPS coax, the other one, there's the switch, now switching it to the HF radio. <p> Why didn't the sound change, actually, come to think of it, what sound? Hmm, the audio is going into, nothing, actually, it's going into the audio mixer that's turned off. Turn that on. Then audio at last, nope. Hmm, oh wait, the audio needs to go from the HF radio, not the VHF radio that's configured to do some audio spectrum recording. Turn off the Raspberry Pi at the same time, since there's no more audio going into that and who needs more potential noise? Locate the two audio plugs that go into the radio audio adaptor, disconnect the Pi audio, connect the radio audio, now, which one is the microphone? <p> Now I've got it all plugged in, still no audio. Hmm, two of the mixer channels are muted. Turn on one, radio goes into TX, that's not good. Turn it off, radio stops transmitting, sigh of relief. Turn on the other channel, finally hear some squeaky sounds. Ahha, it's coming from the headset. <p> Don the headset, now I've got glorious mono in my brain. Test the microphone, nothing. Hmm, ah the switch on the microphone lead. Now I've got RX and TX going. Yay, victory! <p> Now turn on the computer so I can do some logging. Fire up my trusty, wait, which tool? The one I normally use for casual contesting hasn't seen a new version since the author became a silent key, no idea if the rules for this contest are still current, fire up the next one, that needs a brand new configuration file, but that means reading the manual and I've got more important things to do. <p> Try another one, Yes, that's got the rules ready to go. No idea if the rules are current, but at least there's no configuration file to contend with. <p> At this point I'm two hours into my one hour contesting window and I have to stop. Haven't even tuned the antenna and I'm already out of time. <p> Hmm, this shack is rigged. <p> Wonder who I should blame for that? <p> Some days all good intentions come together. Other days they don't. There's always the next contest. <p> Lessons learnt, my shack needs a serious rethink on how best to set it up so I can operate daily, experiment and accommodate a casual contest. Looks like I'm off to the hardware store for some brackets and my documentation clearly needs updating, actually, truthfully, needs writing. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Planning for an emergency...
Foundations of Amateur Radio <p> Identifying the problem is the first step in fixing it and with that I want to talk about emergencies. One of the very first things I was told about our amateur radio community was that we're here for when emergencies happen. Our purpose is to communicate, so in a crisis, we can assist by supplying communication to the situation. <p> I've talked about some of this before. Preparedness in the way of on-air training by contesting, in getting gear ready and even exercises for when this occurs. There are amateur clubs dedicated to putting up repeaters for just such an eventuality. <p> Recently there was a local news item about radio amateurs banding together, sending gear to fellow amateurs who were hit by severe flooding that wiped out their shack and with it their ability to communicate. <p> Another event was a friend who lost a big chunk of his shack when his basement flooded. <p> Across Australia and in other parts of the world in recent times we've been witness to the most devastating fires that destroyed entire towns and communities, taking with it infrastructure, communications, not to mention stock, local flora and fauna and entire wildlife ecosystems, bringing some to extinction levels. <p> The destruction doesn't end there. War and famine, drought, cyclones, hurricanes or typhoons, snow storms, heatwaves and the like. <p> All those situations can to greater or lesser degree benefit from amateur radio communications, either for amateurs affected, or for the community at large. <p> I started considering what would actually be required to be useful in such a situation. Could you be prepared for anything, or are you required to pick and choose? What does "being prepared" actually look like and what steps can you take once it's happening? <p> I asked myself if sending radio gear to amateurs who are affected by floods is the most effective way to actually help, or would it be better to pass the hat around and send the proceeds to their bank account? <p> Should you as an amateur drive into an emergency area and start communicating, or are there better ways to help? <p> There are local amateur radio emergency service groups under various names in different countries, some of which are highly effective, others much less so. <p> One attempt I made was to join the local volunteer state emergency services. For several reasons that didn't work out for me, but it remains a viable option for some. <p> Joining those types of groups gives you a framework, but does it actually answer the underlying question, that of effectiveness? <p> I have a drawer full of emergency service training manuals, each more dense than the next, but very little of it relates to the amateur radio. Many pages are dedicated to search and rescue, staying alert, first aid, keeping alive, hand signals, log books, mapping and the like. <p> I am left wondering why we as a community, with a proud century of activity, having one of the main principles as emergency communication appear to have such a poor track record of actually considering what dealing with an emergency looks like and what your own individual place could be in that situation. <p> We document our radios, antennas, power supplies, contacts, circuit board designs, contesting procedures and all the rest of it, but we don't seem to do the same for emergencies. <p> Why is that? <p> In my opinion, it's time to document emergency amateur radio and if you have already started, get in touch. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Why do we communicate?
Foundations of Amateur Radio <p> The art of amateur radio is many things to many people. For me it's a technological challenge, a learning, a way to broaden my experience, a way to be technically active away from my consultancy. The place that amateur radio takes in your life might be the same, or it might be completely different, as varied as the people I've encountered since I became an amateur. <p> People from all walks of life with different experiences and vastly different stories. Truth be told, in the decade that I've been an amateur, I've spoken to and met people from more diverse backgrounds than in the forty years before that. I make that statement as a person who migrated across the globe twice, travelled through a dozen or so countries, stood on stage in front of thousands of people, taught countless classes and as a radio broadcaster interviewed people from all over the planet. <p> From paraplegic to quadriplegics, from people with terminal diseases to people struggling with their identity, from astronomers to astrologers, from train drivers to truck drivers, from mariners to motorcyclists, from working to retired, from healthy to hospitalised, from local to remote, from energetic to sedentary, from happy to sad, from connected to isolated and everything in between. <p> As a host of a weekly net for new and returning amateurs I've begun to notice that some people are falling away, either sitting on the side because they feel that they have nothing to contribute, or stopping communication altogether. <p> It occurred to me that for some people amateur radio is the only way that they connect to the world around them. It's the only way for them to meet people who are different, who walk a different path, who tell a different story. It's also sometimes the only thing that makes them get out of bed. <p> In a world where we're all busy, dealing with the realities of daily life, trying hard to figure out what our place is in that experience and trying hard not to lose your identity while you're attempting this, it's easy to overlook the amateur you didn't hear from for a week or a month. <p> I know that for several of my new friends, amateur radio kept them alive for longer and made them smile more often and made their life a little easier, even if several of them have become a Silent Key since I counted them as my friend. <p> When one of the main activities of our hobby is communication, it seems appropriate to take a moment to consider what that looks like from the other person's perspective. What might it be like to be acknowledged, to be validated as a human, to see them and their life, to speak with them, even if only briefly, and to take a moment out of our own busy existence and answer that CQ, or respond to a question, or smile with a fellow amateur. <p> There is another aspect to this, one which I've not actually seen in the amateur community. Perhaps I've been too busy to notice, but it appears that the venerable telephone circle, the idea that one person calls the next person on the list, who then calls the next and so-on. If the last person doesn't get a call within a set time, they call the list backwards and discover who is not answering their phone. It's an effective way for people to regularly talk to each other and it's an excellent way to make sure that everyone is OK. <p> In our own community of amateurs we can do the very same thing. Hosting a net is one way, having a daily commuter chat is another, but when you do this, take a moment to consider who didn't check in and see what they're up to. <p> It's fascinating to me that we're a hobby that's primarily made of old men, yet we haven't actually embraced our own ageing process as part of the experience. Sure there is a need to encourage new people into the hobby, but that's not the entire story. We should be so lucky as to speak with our friends on a regular basis, to check-in with each other and to make sure that we're all getting our daily dose of RF. <p> So, ask yourself how the community around you is doing and how you might take a moment to check-in with those not so near, but just as dear to you. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Introduction to the terms of contesting
Foundations of Amateur Radio <p> One of my favourite activities is contesting. Essentially it's a time-limited activation of your station for the purposes of testing your skill and station against other participants. Contests are controlled by rules as varied as the amateur community itself. <p> That said, there are common terms and concepts and if you're not familiar with them, they can lead to confusion and disappointment when you inadvertently break a rule and see your hard work vanish into thin air. <p> I will note that what I'm discussing here is not universally true, so read the rules for each contest you participate in, something you should already be doing since rules are refined over time and it's rare to keep the same rules between years. <p> A contest starts and stops at a specific time, often expressed in UTC, or Universal Coordinated Time. You should know what your local timezone is in relation to UTC and take into account any variations like Summer and Winter time. Any contacts made outside these times don't count and you cannot log these against the contest. <p> Each contact or QSO is awarded a set number of points. It might be scored based on mode, band, power, time and sometimes distance. To encourage specific types of contacts, some might attract a score of zero. This does not mean that the contact is useless, which I'll get to shortly. <p> Your score is the sum of all the points you make for each contact. I will mention that contest logging software can track this to make your life easier, although it comes at the price of requiring a computer. <p> Sometimes a prohibited contact attracts penalties. Prohibited, as-in, by the rules of that contest. For example, some allow you to contact the same station more than once, others allow this only if you do it on a different band. <p> Speaking of bands. It's not permitted to make contest contacts on the WARC bands. In 1979, the World Administrative Radio Conference allocated the 30m, 17m and 12m bands for amateur use. These are not used for contesting. To avoid a contest, you can use those bands, but truth be told, you should try to use all the bands, even during contests, since it will help you operate your station in adverse conditions, something worth practising. <p> Many contests allocate additional scoring based on state, country, DXCC entity, CQ or ITU zone, prefix, or all of these together. <p> Both the CQ and ITU zones represent regions of the world. The CQ zones are managed by CQ Magazine and the ITU zones are managed by the International Telecommunications Union. A zone is represented by a number. <p> The DXCC is a system that tracks individual countries across the globe. If you make contact with 100 of these places, you've achieved your DX Century and you join the DX Century Club, or DXCC. <p> Consider a contact with me. You'd have a contact with VK6FLAB. It would also be a contact with the VK6 prefix, the VK DXCC entity, CQ zone 29 and ITU zone 58. If that's not enough, it would also be a contact with OC-001, the IOTA or Islands On The Air designation for Australia. <p> This is useful because for some contests these extra features represent points, often significant ones, generally referred to as a "multiplier". <p> To calculate your score, tally up all your contact points, then count all the features, CQ Zones, the ITU Zones, DXCC entities, states, countries, etc. and multiply your score with that count. If you contact 10 callsigns and get one point for each, you have 10 points. If in doing so you contact five contest features, you end up with an overall score of 50 points. <p> Often contests have different categories and rules for transmitter power level, the number of transmitters and the number of operators. <p> Definitions for these vary. High Power might be 400 Watts in Australia, but 1500 Watts in the United States. QRP or very low power might be 10 Watts in one contest, but 5 in another, so check. <p> Some contests have an assisted category where you're permitted to use tools like the DX Cluster where other stations alert you online to their presence on a particular frequency. <p> There is a concept of an overlay, where how long you've held your license, your age, working portable, battery operated, using a wire antenna or mobile, groups you with others doing the same thing. This means that you could be a rookie, youth, portable, battery, wire antenna, single assisted operator, all at the same time. It often pays to consider who else is in a particular group and make your claims accordingly. <p> If you're contesting with more than one person, a Multi station, there are rules for that too. Sometimes this includes the amount of land a contest station is permitted to use. <p> If you're a Multi-Single station, you might be permitted to use one transmitted signal on one band during any 10 minute period. <p> A Multi-Two might be permitted to use two simultaneous transmitted signals, but they must be on two different bands. <p> A Multi-Multi may activate all six contest bands at the same time, but only use one transmitter per band. <p> Some contests have a Short Wave Listener or SWL category, where you log all stations heard. There is also the concept of a check-log, where you log all your contacts, submit them, but don't enter the contest itself. You might have worked stations during the contest, but not according to the rules, because you might be aiming to get your DXCC. Submitting your log will help the contest organisers check other entries and validate the scores of the stations you contacted. <p> This might all be daunting, but if you read the rules of a contest and you're not sure, every contest manager I've ever spoken to is more than happy to help you understand what's allowed and what isn't. <p> One tip. Contesting is as much about the rules that are written as it is about the rules that are not. If you find a gap in the rules, and it doesn't go against the spirit of the contest, you're absolutely encouraged to use that to your advantage. If you do, you'll quickly discover why the rules change so often. <p> Preparation is everything! <p> I'm Onno VKFLAB
Listen: podcast - audio/mp3

It beeps!
Foundations of Amateur Radio <p> After weeks of attempting to get some noise, any noise out of my PlutoSDR I have finally cracked it. Not sure if cracked it refers to my sanity or the outcome, but beeping was heard from the Pluto on my radio, so I'm doing victory laps around the house, all conquering hero type affair, complete with whooping and hand waving. <p> In the end it all came down to serendipity and truth be told, I know it beeps, I've heard it beep, it does so on a predictable frequency, but why it exactly works is still a mystery that has yet to be discovered since the documentation I have isn't sharing and the example code I have contradicts what I'm seeing. <p> For context, a PlutoSDR, or Pluto, is a very capable software defined radio, perfect for experimentation. I've talked about it before in the context of using it as a receiver. <p> My most recent efforts involved coaxing my Pluto out of a corner after it sat there sulking for weeks. Turns out that not only was my USB power lead broken, which caused the blinken lights to stay off. When I finally figured that out, I discovered that one of the two wireless dongles I'd purchased together was Dead On Arrival. After a frustrating morning with the manufacturer who wouldn't take my word for it that swapping out the two identical units would not require installing the driver, something about Windows Device Manager on my Linux computer, I went back to the store who happily swapped out the faulty device on the spot. Mind you, the Pluto still isn't talking to my wireless network, but at least it's not the dongle anymore. <p> I plugged the Pluto into the back of my main workstation and discovered to my surprise that in addition to showing up as a thumb-drive, which I knew about, it also turned up as a network device, which I didn't know about. <p> It's been a while since I powered this up to play, so I updated the firmware which fixed some annoying issues and started to explore. <p> The aim of my quest was to create a proof of concept beep from the command-line on the Pluto. <p> If you're not familiar with this. The Pluto is running a flavour of Linux. You can connect to its command-line and run commands from inside the hardware. <p> This is important because for most radios, of both the analogue and software kind, you generate the information somewhere, like Morse Code, a WSPR signal, your voice, what-ever and then you send that to the radio. On an analogue radio it's likely to go across an audio cable of some sort and if you have a software defined radio, it's likely to travel from your computer across a USB or network cable to the radio to get processed. <p> This is different in that there is no such signal coming across the USB link. The link is used as a network cable to ssh into the radio where you can generate whatever you want. In my case Morse. If you're not familiar with ssh, think of it as a keyboard connection to a remote computer. <p> My script, hacked together as it is, more on that shortly, takes a string, like say "CQ DE VK6FLAB" and processes that character by character. It converts each into the equivalent Morse code dits and dahs and then uses those to turn on a test tone for an appropriate amount of time. <p> So, to send "CQ", the script changes that into -.-. --.- and then turns on the transmitter for three units, off for one, on for one, off for one, on for three, off for one, etc. <p> This is Morse code at its very simplest, the software equivalent of holding down a Morse key for the correct amount of time and then releasing it. <p> I disparagingly called it hacked together, because it's using the in-built busybox command shell that comes with the Pluto. If you're familiar, the actual shell is called ash, or Almquist shell. It's strictly limited in functionality, no arrays, minimal redirection, all very basic. Perfect for what I want to do, but not so much if you want to write software. <p> After working around the lack of arrays, one of the things that caused me the most problems was to discover just how to setup the Pluto to actually do this. I found a couple of examples online that pretended to work, claimed to be doing what they said they were, but nothing was heard on my local analogue radio. At one point I heard clicks, but no beeping. <p> After spending literally hours testing, scanning up and down the radio dial with my Yaesu FT-857d, I stumbled on a tone that stopped when my test script stopped. I started the script again and the tone came back. When it ended, the tone stopped again. I finally had a relationship between a tone on the PlutoSDR and the frequency on my radio. <p> So, with all manner of funky offsets in my code, subject to me understanding the how and what of them, I can now beep to my hearts content. Of course I've shared my efforts on github, cunningly called Pluto Beacon. <p> Have a look and tell me what I did wrong. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What happens when you plug it in?
Foundations of Amateur Radio <p> The other day I took delivery of a shiny new circuit board populated with components and connectors. Knowing me, you'd assume that I'd been the recipient of some kind of software defined radio gadget and you'd be right. <p> One of the connectors was a micro USB socket, intended to be used to plug the hardware into a computer and to drive the circuit board. <p> The board came to me by way of a friend who saw it online, waxed lyrical about it and for less than $35, who could begrudge this exploration into a new toy? <p> Once it arrived, it sat on my shelf for a few weeks, enticingly packed in an anti-static bag, transparent enough to see the device inside, taunting me to open it up, plug it in and have some fun. <p> Today I opened it up and started researching my new gadget. It didn't come with any user manual, no URL, no model number, but it did have a callsign on it, so I started there. I'll note that I'm not going to repeat that callsign here for a number of reasons, which I'll get to. <p> My exploration discovered a site where this device was being sold. It also unearthed several international amateur radio forums describing what appeared to be this device, including circuit diagrams and specifications. <p> What I found harder to discover was software. <p> It appears that I have a clone of a device that may still be manufactured, or not, I cannot tell. I found some example code on github for the original hardware, but it seemed to require other libraries, but didn't actually specify those anywhere. <p> I opened up an online translation tool and started translating some of the wording on the circuit board in an attempt to discover just what information was written on the board. <p> The wording was clearly from a different culture, a different perspective and while it claims to come from a maker space that appears to promote women, it also contained a militaristic phrase which caused me to pause. <p> In that moment I came to a sudden and abrupt realisation. <p> How do I know what this piece of hardware actually does? <p> How do I know if when I plug it into the first available USB socket on my computer, it won't install anything nefarious, start connecting to the internet and start doing something unexpected? There's enough hardware on the circuit board to do that and even if the labels on the components tell me that they are a specific integrated circuit, how do I know that it actually is that chip? <p> The chips on this circuit appear to have a lot more connectivity than a simple receiver might warrant. One has 40 pins, the other 32. If the label is accurate, the data sheet for one of the chips indicates that it includes an 8-bit micro controller among its various functions. <p> I'll admit that I'm coming from an IT security background at this and you are free to argue that I'm being paranoid, but does that make me wrong? <p> I know that I don't know enough about this particular board or its origins that for now it's going to remain inside its anti-static bag, taunting me with the possibilities of the connectors it offers, but until I know more about the provenance of this gadget, it's going nowhere near any of my computers. <p> If you have suggestions on how to proceed, don't be shy. I did briefly consider plugging it into a Pi, but how would I know if it updated the firmware, forever compromising that Pi? <p> Don't get me wrong, I'm not saying that this board does any of this. My point is around discovering if it does, or not, one way or another. <p> No doubt some might think I'm overly suspicious and there is truth in that, but in my profession it pays to be vigilant. The underlying issue is that of validation. There's anti-virus software available to deal with malicious code, but how do you do such a thing for malicious hardware? <p> Again, I'm not saying that this circuit board is doing anything other than being a USB connected receiver, but how would you know? How would you verify that? And how do we in the amateur community weed out the nefarious tools from the legitimate ones? <p> I'll leave you with one thought. When was the last time you plugged your phone into a free charger on the bus or at the airport? How do you know that your phone wasn't hacked? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How to compare radios
Foundations of Amateur Radio <p> One of the topics I've been talking about lately is the idea that we might be able to measure the performance of your radio in some meaningful way using equipment that can be either obtained by any amateur, or by introducing a process that allows results to be compared, even if they have been generated differently. <p> Recently I came up with a tool that automatically generates a spectrogram of an audio recording. That on its own isn't particularly interesting, but it's step one in the processing of an audio signal. In addition to the spectrogram, I also created a tool that generates a tone frequency sweep, think of it as a tone that changes frequency over time, let's call it a sweep. <p> If you combine the two, you can generate a spectrogram of the sweep to give you a starting point or baseline for comparison. You can build on that by using your radio to transmit that sweep and record the result using a receiver. In my initial experiments, I used an RTLSDR dongle to receive the audio with some success and a boatload of spectacular harmonics, but I wanted to find a better, more accessible way to do this and during the week I realised that my Yaesu FT-857d that's sitting in my shack, is connected to a perfectly functional antenna and with a few settings it could do the job perfectly. <p> One of the biggest issues with my RTLSDR setup was squelch. That is the difference between what is a legitimate transmission and what is noise. Set it too high and you hear nothing, set it too low and you hear everything, including background noise. <p> Since the VHF or 2m noise levels are quite high at my location, or QTH, I normally have the squelch completely closed. This is fine if you're normally using a strong repeater, but if you're attempting to receive a weak hand-held, that's never going to work. <p> As any self-respecting amateur I was dragged down the path of last resort to read my user manual where I discovered that in addition to CTCSS, a way to transmit a tone to open a repeater, there's also a setting called Tone Squelch or on my radio TSQ, which will keep my radio squelch closed, unless it hears the CTCSS tone from another radio. <p> Truth be told, I had to read a different user manual to discover how to actually set the CTCSS tone on my handheld to test, but that's just adding insult to injury. It has been a while since I read any manual, even though I try to get to it once a year or so. I blame it on the lack of field-day camping. That's my story and I'm sticking to it. <p> So, combining all this, the spectrogram generator, the sweep, CTCSS, and adding a Raspberry Pi with some website magic, if you're interested, an AWS S3 bucket, I now have a service that listens on a local frequency, opens the squelch if it hears the correct CTCSS tone, records the incoming signal until it stops, then generates a spectrogram from that audio and uploads it to a web site. <p> None of this is particularly complicated, though I did have some bugs to work through. I've published the code as a branch to my existing frequency-response project on github and I've asked my local community to experiment with what I have on-air before I start doing more far reaching experiments. <p> For example. <p> If I were to tune my radio to a local repeater output frequency, rather than the simplex one I'm currently on, I'd be able to record and generate spectrograms for each transmission coming from that repeater. If that repeater was connected to the internet, using AllStar, IRLP, Echolink, DMR or Brandmeister, or even all of them, the global community could send their audio to my recorder and it could generate a spectrogram on the spot. <p> If using that repeater, you played a sweep into your microphone, or used your digital audio interface to play the sound, you could then compare your signal path against others and against the baseline response. <p> One of the issues with doing this is that much of the audio that travels across the internet is pretty munched, that is, it's compressed, frequencies are cut-off, there's all manner of interesting harmonics and the value of the comparison appears limited at best. <p> Once I have my multi-band HF antenna, which I'm told is still being built, I intend to set this contraption up on HF where we can do point-to-point recordings and we end up having a direct comparison between two stations who transmit into my frequency-response software. <p> I should add some disclaimers here too. At the moment I'm only using FM. The intent is to get this to a point where I can compare any mode, but when I move to HF, I'll likely start with Single Side Band and go on from there. <p> One other annoyance is that any user needs to configure CTCSS to make this work, which is yet another hurdle to overcome, not insurmountable, but I like to keep things simple when you're starting to learn. <p> Also, the harmonics still show, even on an analogue radio, so there's plenty more to discover. <p> In the meantime, what kinds of things can you think of to use this for? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Pictures can say more than words
Foundations of Amateur Radio <p> Recently I've spoken about measuring the frequency response of your radio and what the benefits of doing so might be. Today I've got some progress to report and some initial discoveries. Again, this is preliminary, but then all of this hobby is experimentation, so that should come as no surprise. <p> Let's start with the mechanics of what I'm doing and a "duh" moment I need to confess. <p> The aim of this process is to transmit a known audio signal, receive it, record it and create a spectrogram from it. This allows us to compare the original spectrogram against the received one and show just how the audio path has been affected by getting the audio into the transmitter, the processing by the transmitter, the propagation between the transmitter and receiver, the artefacts introduced in the receiver and any recording device. <p> To begin this process I started off with an audio file of my voice. That wasn't very helpful, since it's a complex signal and comparing my voice before and after is a non-trivial process. At some point I intend to come back to voice before and after comparison, but that's on the shelf for now. <p> The audio that I'm using is a frequency sweep, lasting 5 seconds. That is, there's a tone that changes frequency from DC to 5 kHz. When I looked at the spectrogram of that, it shows as a curve with time against frequency. It occurred to me that I could make two of those sweeps at the same time to measure distortion, so I added a reverse frequency sweep from 5 kHz down to DC. Now I've got two crossing lines showing in my spectrogram. <p> To transmit this audio, I'm using the same tool I use to automatically call CQ during a contest. Every so many seconds I transmit this audio into a dummy load and at this point I should mention that my "duh" moment was that I was attempting to transmit into an antenna and record from a dummy load, rather than transmit into a dummy load and record from an antenna. I still cannot believe that I did that. <p> Moving on. <p> The recording is done using an RTLSDR dongle. In the current initial version I'm using a tool called rtl_fm to tune the dongle to the same frequency as my transmitter. I send the audio from there to the same tool I used to generate the original audio, SoX, that's Sierra, Oscar, X-Ray, and have it detect the silence between each transmission and record each into a new file. If I leave it running, every time I transmit something, SoX will create a new audio file. <p> I'm saying that quite quickly, but getting the squelch and silence detection working in my noisy environment took most of a day and it's specific to my station, today. I'll have to figure out how to make this smarter, but for now I have some data. <p> A spectrogram is generated for each audio file and then we can compare pictures. What was sent, audio wise, and what was received, audio wise. To be clear, I'm not sending images, I'm sending audio and comparing the spectrograms of this audio. <p> I will also note that I'm currently using FM as the mode. I intended to do this with SSB, but the amount of effort to get the squelch right has left me with a future project to achieve that. <p> The code itself is pretty rudimentary, but I've uploaded it to my github page. I've also added the pictures to my project website, which you can find at vk6flab.com. <p> One initial observation, one that I don't yet understand, is that what I sent and what I received don't look the same. My pretty curves in the original audio come back with spectacular harmonics all over the place, very pretty to be sure, but not quite what I was expecting, let's call it an educational challenge. <p> Before I forget, just because I'm using a Yaesu FT-857d, a Raspberry Pi, an RTLSDR dongle, an antenna and a dummy load, doesn't mean that you need to. Essentially, what this does is generate a special audio file, transmit it, receive it, record it and generate a spectrogram. You can play the audio from your own computer if you have digital modes set-up, or from your mobile phone if not. <p> Recording can be something sophisticated with off-air monitoring, or it can be a recorder held in front of your receiver. <p> One final note. You can change settings on both the transmitter and the receiver to see what they do in relation to the audio, so experiment. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Testing your radio's audio frequency response
Foundations of Amateur Radio <p> During the week I was reading a comment from another amateur about digital modes. Tucked inside that comment was a phrase that could easily have been overlooked, but it reminded me that there is plenty to learn and test in the field of amateur radio. <p> The phrase, "requires actual understanding of audio level paths" was uttered by Chris, VK2CJB and it prompted a brief conversation at the time, but I've been working on it ever since. <p> Where I arrived at is an attempt, incomplete as yet, to design a mechanism to show the impact of various transmitter settings on the received audio in such a way that you can test your own gear and see the result. <p> Before I explain how I'm doing this, let me describe why it's important. <p> Using a radio in concept is pretty simple, if you yell into the microphone, the audio comes out distorted and if you whisper, it might also be distorted, but in a different way, neither is conducive to communication. <p> One way to improve this is a tool called the ALC. Using Automatic Level Control as a guide to what level your audio should be is outlined in every amateur radio manual I've seen, but how much it matters and to what extent is left unsaid. If you apply a filter or any number of other fancy options, what happens to your audio? <p> To get some sense of what I'm describing, listening back to your own voice after it comes across HF SSB is surprisingly distorted in comparison to a local recording. <p> You might argue, what's the harm, as long as the other station can hear my voice, we're good to go. <p> Sure, if voice is all you're using, but what if it's data? In that case, the audio you're transmitting is actually encoded digital information. To decode it, the software needs to deal with frequencies, distortion and levels to name a few. <p> In computer science, "garbage in, garbage out" is the concept that flawed, or nonsense input data produces nonsense output. In our case, if you transmit garbage, the receiver is going to start with garbage and what gets decoded is likely not what you expect. <p> Without going into error correction, essentially, the cleaner the path between the transmitter and the receiver, the higher the chances of success and to be fair, you already know this when you attempt to work a pile-up on a noisy band. "Again, again, just the prefix, again!", sound familiar? <p> To achieve this I started with the idea that you could transmit a tone and if you knew what it was, you could determine the difference between what was sent and what was received. <p> My first step was to generate a single 1 kHz tone, but then I wondered what would happen if you did multiple tones, one after the other. My current version is an audio frequency sweep, running from 0 to 5 kHz in five seconds. It's essentially a computer generated sequence of tones with known characteristics. You transmit this audio file using your radio and then record it off air, either from a local receiver, WebSDR, or the radio belonging to a friend. <p> Using the recording, you can create a spectrogram, a picture, showing the frequencies over time present in the audio. Compare the two and you just learnt what each setting on your radio does precisely to the audio. <p> Of course it's simple for me to say this, but I'm working on using a tool I've spoken about before, csdr, to do the heavy lifting, so you can actually do a meaningful comparison between the various audio files. <p> In the mean time, I've managed to use SoX, the so-called Swiss Army knife of sound processing programs to both generate the audio sweep and draw a preliminary spectrogram. <p> Next up is showing some side-by-side images of various radio settings and their effect on the spectrogram. I'll publish this on my website when I have something to show-and-tell. <p> I also don't yet know if my source audio file is going to be sufficient, but I'll subject that to some testing as well. For example, I'm investigating multiple simultaneous audio sweeps with different frequency ranges. The more complex the spectrogram, the more we might be able to learn from the distortion on receive, but time will tell. <p> If you have some ideas on how to improve this, let me know. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What's in a Dream?
Foundations of Amateur Radio <p> On the 6th of June, 2004, two Brazilian amateurs Roland, PY4ZBZ and Arnaldo, PY4BL made a historic contact on 40m. The distance was not particularly significant, only 70 km, but the mode was. <p> Using 2.1 kHz bandwidth, so it could fit within an amateur radio SSB transmission, they used software created by Swiss amateur Francesco, HB9TLK to make the very first HamDream exchange. <p> This technological advancement represents the birth of what we now call HamDRM and Digital SSTV and how it came about is an adventure that needs documenting, since what we have is written in a combination of Portuguese, German and English, cobbled together from broken websites, archives, source code, commit comments and lost links. <p> To provide some context, there is a broadcast radio mode called DRM, or Digital Radio Mondiale. At this point I should mention that this has absolutely nothing to do with Digital Rights Management with the catchy acronym of, you guessed it, DRM. As you might expect, this acronym clash is unhelpful, to say the least, when you're trying to find information about this radio mode. <p> Digital Radio Mondiale, or DRM, essentially defines a digital standard for radio broadcast transmissions. It can handle multiple audio streams as well as file exchange and is used by broadcasters across the globe. Mondiale, in case you're curious means worldwide in French, seems my high school language lessons have finally been put to good use, my French teacher in the Netherlands will be thrilled. <p> DRM is more efficient than AM and FM and as an open standard, it's gaining popularity. The first broadcast using this mode took place on the 16th of June 2003, during the World Radiocommunication Conference in Geneva. <p> An open source implementation of this mode is called Dream. The source code is available online and is capable of being compiled for Windows, MacOS and Linux. Dream was originally written by Volker Fischer and Alexander Kurpiers. The Dream project started in June of 2001 and today it has many contributors. <p> The DRM standard uses different bandwidths depending on which mode is used. The narrowest DRM mode uses 4.5 kHz, but modes using 100 kHz exist. By comparison, a typical analogue amateur radio uses 2.7 kHz for SSB. Using the source of Dream, Francesco built a modified version, called it HamDream and let it loose on the world. It was used for that very first 70 km contact between Roland and Arnaldo. <p> Several versions of HamDream existed. The first QSO used 2.1 kHz and the last version of HamDream used 2.5 kHz bandwidth. To fit digital audio inside that narrow bandwidth it used different audio compression techniques, called a CODEC, namely LPC10 and SPEEX. <p> According to Francesco, HamDream is the basis for all current amateur radio 2.5 kHz HamDRM programs. He goes on to say that it's outdated and the source and executables were removed from the net. Personally I think that's a shame, since it represents part of the history of our community and I think that putting the source online in a place like GitHub would be beneficial to the hobby. <p> The 2.5 kHz HamDRM mode is implemented in several places. QSSTV, EasyPal and WinDRM to name a few. No doubt it's elsewhere. Of those three, only QSSTV survives. The source code for EasyPal, written by Erik VK4AES, now SK, was lost, apparently when the computer on which it lived was sold by his estate. Ironic really, since EasyPal was written because Erik lost a previous application due to a lightning strike nearby and was forced to write a new application from scratch. <p> WinDRM appears even more elusive. There's a repository on the now archived Google Code site. There are derivatives that appear to use a version of WinDRM, but details are hard to find. An archive I have shows a commit by Francesco, HB9TLK from 2008. I've yet to learn how this relates to the overall picture. <p> In parallel, in 2005, a few enterprising students made a MATLAB implementation of DRM. Called Diorama and written by Andreas Dittrich and Torsten Schorr it forms the basis of a Linux open source HamDRM receiver written by Ties, PA0MBO, chosen because it had a better performance in marginal conditions than Dream did. It's called RXAMADRM. Ties also wrote an open source transmitter, cunningly called TXAMADRM. It was based on the source code of Dream, specifically v1.12b. <p> If at this point your head is exploding, I wouldn't blame you. <p> Let's recap. <p> There's an open broadcast standard called DRM. An open source, cross platform tool called Dream, in active development, implements that standard. <p> A special, now discontinued, version of Dream was created called HamDream. It used less bandwidth than DRM and forms the basis of a standard that we now call HamDRM, which underpins Digital SSTV. <p> HamDream forms the basis of the discontinued products, EasyPal and WinDRM, and lives on in TRXAMADRM and QSSTV, both Linux open source. <p> In amateur radio terms HamDRM is one of the ways we can efficiently exchange digital information across long distances. <p> At this point you might wonder why it matters? <p> For starters, this is part of our history of amateur radio. The HamDRM mode is poorly documented, if at all. It forms the basis of several modes in use today and writing your own software is made all the more challenging because much of the design and development of this mode has been lost. <p> What's more, HamDRM is an example of "modern radio". It uses the same fundamental techniques used by the 4G and 5G mobile phone network, as well as modern Wi-Fi. Losing this is a massive step backwards for amateur radio. <p> This article alone represents a week of research by two people, thank you Randall VK6WR, and I won't be surprised to learn that it contains errors and omissions. It shouldn't have to be this hard to discover how a mode works, what is used to make it tick and how to write new software to implement a new application. <p> Gotta love open source. Speaking of which. If you have source code copies of HamDream or WinDRM, I'd love to hear from you. cq@vk6flab.com is my address. If you have documentation on the design of the HamDRM mode, I'll owe you a beer, or a glass of milk, your choice. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Bringing an upconverter into your life
Foundations of Amateur Radio <p> A couple of days ago, after months of anticipation, an unassuming little box arrived on my doorstep. Inside the box was a nondescript electronic device with two SMA connectors and a USB socket. Other than the branding, there were no markings on the device and it came without any instructions. <p> It did come with a couple of SMA adaptors, which came in handy. <p> A little research later determined which of the two SMA adaptors connected to an antenna and which connected to a radio. <p> The gadget itself is called an upconverter. <p> It's an interesting little device that essentially mixes two frequencies together, creating two new ones, start with say 720 kHz and mix it with 120 MHz and you end up with 120.720 MHz and 119.28 MHz. In other words, if you mix two frequencies together, you end up with both the sum and the difference of those frequencies. <p> If you have a radio that can listen to 120 MHz, but cannot listen to 720 kHz, then using an upconverter, you can, as it were, expand the frequency range of your radio to hear different signals. <p> I purchased the upconverter with the intent of connecting it to my PlutoSDR, since the lowest frequency it can do is 70 MHz. Combine the two and I should be able to listen to all of the amateur HF frequencies at once. <p> Given that my PlutoSDR is currently doing something else, I had a look at using the upconverter with my WSPR beacon monitor that uses an RTL-SDR dongle. Technically it's not required, since my particular dongle can be used to tune to HF frequencies, but as an experiment, it works well enough. <p> So, I connected the antenna to the upconverter, the upconverter to the dongle and the dongle to a Raspberry Pi, a single board computer that runs Linux. Essentially the exact same setup I've been running for years, except that I inserted the upconverter between the dongle and the antenna. <p> That and some power took care of the hardware. <p> The software initially gave me some challenges. After discovering that the tool I'm using, rtlsdr_wsprd, has an option for an upconverter, I was up and running in minutes. <p> So, at the moment, and for the next foreseeable little while, my WSPR monitor is using an upconverter to scan HF. Technically this should increase the sensitivity by a significant amount, since the dongle is better suited to tuning to higher frequencies than it is to lower ones, but only time will tell. <p> I updated my monitoring scripts to take into account if the frequency I was monitoring was out of range, so it currently won't report on anything above 60 MHz, but then that's fine for what I'm working on. <p> I've updated the script on github if you want to have a look. It's nothing fancy, it essentially checks to see if there's a file called upconverter and if so, it calls a slightly different monitoring script. <p> Given that I have existing logging data associated with this monitor, I should be able to discover if there's any significant difference between what I've been monitoring to date and what's coming in now that an upconverter is in the listening chain. Theoretically, I should be able to hear weaker signals, but time will tell. <p> One thing that was interesting whilst I was discovering how this all works and hangs together is that it wasn't immediately obvious how to set it all up in software. I tried several tools to make sense of the data. In the end the combination of gqrx, setting the local oscillator offset to a negative frequency, in my case 120 MHz, got me to the point where I could set the frequency to 720 kHz and hear my local broadcast station, whilst the software actually, secretly behind the scenes, added 120 MHz to that and tuned the radio to 120.720 MHz. <p> Once I got my head around that, things started falling into place. <p> The same is true for rtlsdr_wsprd, adding the upconverter flag with the value of 120MHz, got my monitoring station up and running. <p> This is a pretty user friendly way of getting started with frequency mixers. You might recall my exploration into components apparently made from unobtainium. The intent is to use a variable frequency to achieve a similar thing, but that's a project still on the drawing board, for now, I have a fixed frequency, 120 MHz, which is plenty to get started. <p> If you're curious why I'd want a stable variable frequency, consider for example, what might happen if you transmit from a HF frequency into an upconverter. Perhaps you could use your HF capable WSPR beacon to make a signal on 2m or 70cm. 120 MHz won't cut it, but perhaps you can work out what's needed to get from the 10m WSPR band to the 2m WSPR band, or the 70cm WSPR band. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

When I said Parrot Repeater ... I likely had a different picture in mind.
Foundations of Amateur Radio <p> A little while ago I mentioned in passing that I was considering implementing a parrot repeater to help determine how your radio is performing. Discussion afterwards revealed that not everyone had the same picture in mind, so I thought I'd share with you some of what I'm considering and why. <p> Most of the modern radio landscape revolves around hooking a computer up to some type of radio frequency capable device. Commonly it's the audio and control signals that travel between computer and radio, but there are plenty of examples where raw data makes the journey, like in the case of an RTL-SDR dongle. <p> That journey is increasingly made using USB, the cable, not the sideband, and limits are based around the maximum speed that a Universal Serial Bus has. Essentially the amount of data that you can process is limited by how fast your computer can talk to the radio. <p> For my parrot repeater, I'm imagining a device that can receive RF from any radio and process that signal to determine what the centre frequency is, the deviation, stability, the mode, what ever parameters I end up being able to determine, a whole other discussion on its own. In response, the idea is that the device generates a report and either presents that using text to speech, or as a web-page, or both. <p> Using traditional methods, this would involve a radio, a computer, some software, connections between the radio and the computer, not to mention power for both the computer and the radio, an antenna and perhaps an amplifier. The picture I have in mind is not anything like that. I'm imagining a single device that takes power and does all I've described inside the one device. No external computer, no audio cables, no control cables, no hard drives, not anything, just a PlutoSDR and a power source connected to an antenna or two. <p> You might think that's fanciful. As it happens, we already have some of that today. When I run dump1090 on my PlutoSDR, it presents itself to the world as a website that I can visit to see which aeroplanes are within range, where they are exactly on a map, what messages they're sending and where they're going. All of the processing is done inside the PlutoSDR. All I have to do is give it power and an internet connection. <p> This is possible because the PlutoSDR is essentially a computer with RF. It runs Linux and you can write software for it. Unlike my Yaesu FT-857d, which also has a computer on board, rudimentary to be sure, but a computer none the less, it cannot be altered. I cannot load my own piece of software, launch a web browser and point it at my Yaesu, not without connecting an external computer that in turn needs to be connected to the radio. I might add, that this is is how many repeaters work and how devices that implement AllStar and Echolink manage to make the jump between the Internet and the world of RF. <p> If your eyes are not lighting up right now, let me see if I can put it in different terms. <p> The PlutoSDR has the ability to access signals between 70 MHz and 6 GHz. It can do so in chunks of 56 MHz. Said differently, if you were able to consider all of the amateur HF spectrum, from zero to 54 MHz, you could fit all of it inside one chunk of 56 MHz that the PlutoSDR is capable of. You couldn't send it anywhere, since you're limited to how fast a USB cable is, but you could technically process that inside the PlutoSDR itself. <p> To get the PlutoSDR to see the amateur HF bands you could connect it to a transverter, in much the same way that today many 2m handheld radio owners use a transverter to get to 23cm, except in this case, we're going the other way. <p> In order to actually use this massive amount of information, you're going to need to do some serious signal processing. Accessing 56 MHz of raw data is hard work, even if you don't have to get it across a serial connection. As it happens, the PlutoSDR also comes with an FPGA. As I've mentioned previously, it's like having a programmable circuit board, which can be programmed to do that signal processing for you. It has the capability to massage that massive chunk of data into something more reasonable. For example, you might be able to use it to extract each of the amateur bands individually and represent them as an image that you might show to the world as a waterfall on a web browser. <p> Now to be clear, I'm not saying that any of this exists just yet, or fits within the existing hardware constraints. I'm only starting on this journey. I'll be learning much along the way. No doubt I'll be using existing examples, tweaking them to the point that I understand what they do and how they work. I've already been talking about some of this for years. As you might have discovered, this adventure is long with many different side quests and at the rate I'm going I'm confident that this represents the breadth and depth of what amateur radio means to me. <p> So, if you're wondering why I'm excited, it's because the amateur radio world of opportunity is getting bigger, not smaller. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Products made from unobtainium
Foundations of Amateur Radio <p> The other day I received an email from a fellow amateur, Elwood WB0OEW. We've been exchanging email for a little while and having been in the hobby since before I learnt to ride a bicycle, he's always got some interesting insight into something I've said and an encouraging word to share. <p> This time he introduced me to a project he built and published a couple of years ago. It's a variable frequency standard, built from parts and, at the time, costing all of about $150, more on that shortly. Compared to the microwave oven sized HP-606A signal generator sitting on my bench in bits, with some diligent layout, this project could fit inside one of the valves that drives that massive hunk of equipment. <p> As an aside, truth be told, I'm a little afraid of the HP. It managed to pop the RCD, a residual current device, or safety switch, in my house and in doing so, took out the UPS that powers my main workstation, so, not unexpectedly, I'm reluctant to repeat the experience. Once I understand precisely what happened, I'll pick up the restoration efforts and based on what I learnt today, it might get me where I want to go faster. <p> Elwood's frequency standard is a very interesting project that delivers a very precise Variable Frequency Oscillator or VFO with an accuracy approaching 1 part per billion. His project uses an Arduino to control a touch sensitive display, read a knob and set and correct the frequency using a GPS as an accurate external time source. It's all very compact, easy to follow and I immediately thought that this would be an excellent project to build with a little twist. <p> I'm thinking that it would be really great to have this device sit on your local network and make it remote controllable. <p> The heart of this frequency standard project is a chip called an Si5351. The Silicon Labs Si5351, to use its full name, was first sold by Mouser in 2010 and has been popular since. You'll find it in all manner of places, including the Linux kernel source tree, the QRPlabs QCX and BITX to name two, the Elecraft KX2, scores of Arduino projects and countless frequency source products and projects used in amateur radio. <p> The Si5351 is a configurable clock generator. Think of it as a programmable crystal that can be configured on the fly, as often as you like. For configuration, it uses an I2C bus, or Inter-Integrated Circuit communications protocol, a special serial bus intended for chip to chip communications, invented by Philips Semiconductors in 1982. That's the same Philips from the light bulbs and audio cassettes, CD, DVD and Blu-ray, also the Philishave. To complete the picture, Philips Semiconductors became NXP in September 2006. <p> Back to our frequency standard project. <p> I wondered if I could cut out the Arduino from the actual correction process, since I didn't need a display or a knob and discovered that the Si5351 comes in several flavours. Elwood's design uses the A-version, but there's also a C-version that has the ability to take in an external clock, like say that from a GPS, and correct within the chip itself. <p> With that information in hand, I figured that I could use a simple Wi-Fi capable system on a chip, something like say an ESP8266, to configure the clock and take care of communications with the outside world. In the process I'd learn how to do a bunch of new things, including my first foray into generating RF, first time writing actual firmware, first time designing circuits and no double many more firsts. <p> Then I hit a snag. <p> It seems that the Si5351 has gone from commonplace to zero in stock. Not just zero in stock in Australia, or the US, no, zero in stock anywhere. There are a few A-version breakout boards, that is, the chip on a circuit board, available from one supplier. There is also a new compatible chip, an MS5351M, available from China, but that's a drop-in for the A-version, not the C-version. <p> So, where it stands is that I can almost taste the design, essentially three chips, an almost trivial circuit board, some SMA connectors, a power source and an external GPS antenna, something that would represent the very first circuit I actually designed, which is a long way from reading the circuit diagram for my Commodore VIC-20 back in the days before I owned a soldering iron. <p> It did bring me face to face with an odd realisation. <p> There are components that we use in day-to-day use, ones that are common, used across many different industries, that come from a single source. I should also mention that this particular manufacturer just got sold to another company, which doesn't help matters. <p> Nobody seems to know how long this shortage might last with forecasts varying wildly, but I'm beginning to wonder how many of these kinds of components exist and how we might reduce our dependence on single supplier hardware. <p> I'm also starting to look at using an FPGA to do all of this in software, but that's going to take some time, of course we could start using valves again. My 1960's era HP signal generator is starting to look much less intimidating. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Leaving the hobby ...
Foundations of Amateur Radio <p> The other day I came across a how to video on becoming a radio amateur. It's a recurring kind of publication, the kind that I've contributed to in the past. <p> I wondered what it would take to leave the hobby. <p> First of all, I'd have to let my callsign lapse. That's easy enough, but I paid for five years, so it's going to take a while. When it has finally ceased being mine, have I stopped being an amateur? <p> For one, my qualifications would still be in the regulator's database, likely well beyond my breathing years. I wonder if they implement the right to be forgotten? <p> Another thing I'd have to do is stop knowing about how antennas work in day-to-day situations. I'd have to stop noticing the location of free to air television antennas, mobile phone towers, Wi-Fi antennas throughout the community and even the network in my home. <p> I'd also have to say goodbye to all the friends I've made around the place. There's hundreds of people scattered around the globe who with a single word might lure me back into their world, and with that the risk of being sucked back into the community once again. <p> At a minimum I'd have to stop using computers, or radios, or electronics really. I'd have to stop wanting gadgets and measuring equipment, not to mention having to mothball my soldering irons and give away all my heat shrink. <p> I'd have to give back the space I've eked out in the house and return it to the general living space it once was. I'd also have to sell all my radio gear and antennas. I'd have to rip out the coax, fix up any holes, cancel pending orders for new antennas and donate my books and magazines to the local library. <p> I'd have to stop looking at electronics magazines, cut up my loyalty cards for the local electronics and hardware stores and start an online store to sell all the connectors and adaptors I've amassed over the time I've been part of the community. <p> I'd have to forget the phonetic alphabet that I use almost daily and start using crazy words to spell things over the phone like a normal person does. <p> Experimentation would be a thing of the past and would be frowned upon as a fringe activity, one only suited to madmen and amateurs, and I'd have to stop investing my time in software and projects that might one day be used in amateur radio. <p> One of the hardest things to give away would be my curiosity, the one thing that's innate to my wellness. I'd have to stop asking Why? and How? all the time. I'd have to plead ignorance when someone asks how coax works and what's inside a blob of goop on a random circuit board they found on the side of the road. <p> Then there's the other things like physics and general science. I'd have to disavow all knowledge of these activities. I'd have to stop looking at the stars and stop wondering which radio frequencies were being emitted from all over the night sky. <p> I'd have to become ignorant of emergency services and communication, of event management and club life. I'd have to feign interest in anything that wasn't science or technology and I'd have to keep a straight face and my mouth shut when someone extolled the virtues of an irrational belief system. <p> I would likely have to give up my job as an IT consultant and start on a more manual job. Perhaps I'd take up gardening, though I'm not sure how I'd do in the weather at my age. <p> Even if I achieved all that, and kept it up for the rest of my life, I'd still be an amateur, just one hiding from the hordes of humanity striving to live on this ball of dirt, hurtling through the heavens on a journey through the stars. <p> I'm not sure I could do that. <p> So, for better or worse, as I see it, once an amateur, always an amateur and if you're curious and believe in science and technology, I'm here to say that you're well over halfway towards being an amateur! Welcome to the club! <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What testing equipment is essential?
Foundations of Amateur Radio <p> After discussing the notion that it's not really possible to determine how your gear is performing without measuring, several people commented that in the good old days an amateur was expected to have sufficient equipment to test performance of their gear. <p> I flippantly pointed out that once upon a time, computers ran on punch cards too. That's not to dismiss the notion of testing, but rather that times have changed. Testing equipment that was suitable in the 1980's is still available around the place, but expect to pay for it. Some of it is still relevant, some less so. <p> Even if you do acquire suitable equipment, how do you know if what you're measuring is real? How do you know if the frequency counter that you have is accurate, how do you know if 1 Volt is 1 Volt, or 1 second is 1 second? As I've said before, measurement is the act of comparing two things. <p> If you think that's ludicrous, consider the rulers and tape measures in your home. They all indicate the same measurement, right? Just for a laugh, pull out all the ones you can find and see what you discover. If you've not done this, you're in for a surprise. <p> I don't want to dissuade you from getting testing equipment, far from it, but don't expect to fork out to get the equipment and call the job done. The point being that spending lots of money on gear isn't the end of the story, it's just the beginning and in my opinion it's not the place you should start. <p> Based on community responses, ninety recommendations in all, so hardly scientific or representative, but still a good feel for the space we're playing in, the single most important piece of equipment you should get after sorting out your radio, antenna, coax, power supply, computer, software and other fun things we fill our shacks with is the Digital Multi Meter. You can spend anywhere from $10 to $500 on one, but it should be high on your list. As with the rulers, your results will vary, so be mindful of that when you go shopping. <p> While the SWR meter and the Watt or Power meter appear regularly, they're not the next highest ranked testing gear. Mind you, most current radios have those built-in to some extent, so perhaps the numbers are somewhat distorted here. <p> The next essential piece of equipment is some form of monitoring. Either active, passive, programmable, automated, manual, what ever. Hardware like the NanoVNA, the TinySA, even using a Software Defined Radio feature high on the list. Most of these devices either generate a signal to test against, or they rely on your radio to do the heavy lifting, depending entirely on what you're testing. An antenna analyser is among these kinds of tools. <p> As an aside, the dummy load, either a high power one, or a more modest one, come recommended by many different people. <p> Together with this list of monitoring equipment comes associated accessories, adaptors, patch leads, attenuators and filters. <p> After that comes equipment such as variable power supplies, Watt meters, grid dip meters, oscilloscopes and frequency counters. <p> I will observe that from the responses I received there was a distinct flavour to the recommendations. <p> On the one hand there was the combination of recommending something like a station monitor, or a signal generator, an oscilloscope and a frequency counter, including things like a Bird 43 RF Watt meter. On the other hand were recommendations for spectrum analysers, NanoVNAs, SDRs and the like. It's not quite across the analogue to digital divide, but it's close. <p> Note at this point that I'm a software guy in the process of restoring an analogue HP 606A Signal Generator from the early 1960's, so I'm not pointing the finger anywhere. <p> There were other tools recommended too, an LCR meter, a tool that allows you to measure Inductance, Capacitance and Resistance, something you can buy in kit form if you want to get started, or similarly, can be purchased for varying amounts of money online. Speaking of money, varying amounts that is, the service monitor was on the wish list for several people. Prices between that of a new radio or a new car with varying amounts of warranty. <p> I will make mention of a bi-directional coupler which was marked as essential by one amateur. It's a tool that allows you to sample a signal in the forward and the reflected path which comes in handy when you're trying to test and build equipment. <p> As mentioned before, your transceiver has some of this equipment built in, or can be set-up to do some of this, so there's no need to go out and spend thousands of dollars to set-up your testing bench on day one, but the day after, I'd add it to my birthday list. <p> No doubt that there's many and varied opinion on this. What is your essential testing equipment? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How does your gear measure up?
Foundations of Amateur Radio <p> When you spend some time in this hobby you're likely to find equipment with similar performance for vastly different pricing. At one end of the spectrum you might compare a cheap $25 hand-held radio to a $450 one. At the other end, a $1,500 SDR or Software Defined Radio against a $4,500 one. <p> Those examples are for brand name devices, which generally speaking have published specifications, come with regulatory approvals, a wide user base, reviews and a distribution network. If equipment is found to be operating out of specification, a regulator might seek a remedy or ban the sale of the equipment. <p> Those various sources and processes make it possible to compare those devices in a structured way to discover just how deep into your pockets you need to reach in order to acquire a shiny new gadget. <p> If you buy any of these devices in the used market, you have no way to determine just how far from the factory specifications the device you're contemplating has deviated. Is that waterproof radio still waterproof, or did the previous owner open up the case and put it together incorrectly? Was it dropped and did a component get damaged? Did the static electricity from a local thunderstorm leak through the circuit via the antenna, or did the previous owner not use anti-static precautions when they looked inside? <p> If it actually failed, it's easy to know. If it's still working, absent a laboratory, you're essentially on your own. <p> If that's not challenging enough, consider hardware that's released as open source, that is, the original designer released their project, shared the design, a circuit board with component list and specifications. Another person can pick up the documentation and legally build a copy of the hardware. <p> How do you know how the two compare? <p> Aside from considering how well any design might actually match the real world, how do you know if the original design can be improved upon or not? Did the second builder use the same components, substitute with better ones, or economise on parts they thought were too expensive? <p> What happens if the two designers argue with each other about the performance of their respective designs? What if the second design becomes vastly more popular than the original and what if you throw in outright intellectual property theft over the top of all this? <p> Now consider the same physical hardware, from the same factory, but using different software. How do you know what impact the software has on the performance of the equipment? For example, one component seen more and more is a chip called an FPGA, a Field Programmable Gate Array. Think of it as a programmable circuit board where updating the software creates a different circuit. <p> An FPGA might be used to filter radio signals. With just a software update, you can program different filters and change the actual performance of the entire device. How do you know if the new version of the software has improved or worsened performance? <p> What all this lacks is a standard way of describing performance. Not only the kind of standard that's achievable in a laboratory, but one that we can test at home. There's no documentation that I've been able to find that shows how to measure some of this objectively, or even compare your own kit against itself. <p> It would be great if I could measure my gear against a standard and you could too and we could compare our respective equipment against each other. <p> Even using the laboratory standard measurements, for example the Sherwood Engineering Receiver Test Data, which allows you to compare other tested equipment in the same list, is hard, if not impossible to compare at home by the likes of you and I. Not to mention that Rob NC0B has finally retired after 45 years, so having been licensed in 1961 age 14, there is a good chance that updates are going to become a thing of the past when Rob stops volunteering his time. <p> I will mention that this isn't a new thing. Many years ago I spent some time as a broadcaster. One of the very first things I was taught is that you need to set levels to trigger the VU Meter just so. When you make a recording to tape, you're required to generate a 1 kHz tone at a specific level so when it's played back to air, the voice levels will be correct. <p> When I became licensed in 2010 I almost immediately discovered that there isn't even a standard way to test if the signal that my radio is putting into the local repeater is the same as that of other amateurs. You'll notice this because you're forever twiddling the volume on your radio when you speak with others on-air because their voice levels vary widely. <p> One idea I've been toying with is using a parrot repeater that can measure a signal, allowing anyone who uses the same parrot to compare their equipment. <p> How would you approach this increasingly complex problem in such a way that the amateur community can share their results in a way that makes comparison meaningful and useful? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Getting Amateur Radio propagation data at home
Foundations of Amateur Radio <p> For some time now I've been discussing the potential of weak signal propagation and its ability to create a live map from the data that your own station transmits. There are several systems in place that show a map of where and when your station was heard in the past little while. Using 200 milliwatts, I've been transmitting a WSPR or Weak Signal Propagation Reporter beacon on 10m for the past few weeks. <p> At the moment, the furthest away my beacon has been heard is 13.612 km away. That's an 0.2 Watt signal heard on the other side of the planet, on 10m. As distance goes, it's a third of the way around the globe. I must point out that there's no way of knowing if this signal travelled the short path or the long path. <p> If you've heard those terms, short and long path but were wondering what they mean, here's how it works. If I get on my bike at my QTH in Perth in VK6 and peddle East until I hit Sydney, I'll have crossed Australia, taken about 184 hours and travelled about 3.746 km. That's the short path. If I head West instead and start swimming, visit Cape Town, Buenos Aires and Auckland along the way, I'll have travelled much further, still made it to Sydney, but taken the long path. <p> Radio waves can do the same. Depending on propagation, a signal might take either the shortest route, or go in the opposite direction and take the longest route along the great circle between two stations. <p> I'm mentioning this because WSPR doesn't tell you if it's one or the other and if you're using a vertical, it could be either. Even directional antennas might receive a signal from unexpected directions. <p> Using one of the mapping tools, wspr.live, I extracted all the sightings of my callsign and all the reports that I'd made from my receiver. It shows that my newest transmitter has now been heard by 11 stations across three continents. <p> Those numbers are just the beginning. I wanted to see on the map where these stations were, so, during the week I built a proof of concept world map that I used to visually show the four character Maidenhead grid squares that my station was heard in. I also had a look to see which stations I'd heard over the years and where they were. In all, 771 different stations are in my log, either as a receiver or a transmitter. <p> N4WQH heard me on 40m, 18.832 km away when I was using 5 Watts. My station has heard, or has been heard across 331 different grid squares. There's reports across some remote parts of Australia, Japan, India, South Africa, Europe, the United States, several across the Pacific and even a few in Antarctica. <p> I wondered how many of the world's grid squares have actually been activated and which station was heard the furthest and how much power was used. Those numbers will have to wait for another day. I initially started using wspr.live which has a neat way of allowing you to embed an SQL query as part of the URL to download the output. <p> I was getting some interesting results, so I thought, rather than hammer this lovely resource with my questions, I should download the raw data instead. So I did. Well, I am. Still. It's big. <p> As of today, there's 166 files, taking up 60 GB of compressed data, with over 3.5 billion reports. <p> The first spot in that data goes to N8FQ who heard WB3ANQ on Monday, the 17th of March, 2008 across 911 km on the 30m band transmitting with 28 dBm, or about 630 mW, reporting a signal to noise ratio of 1 dB. <p> Using preliminary data to get started I mapped all the activated squares, each shown as a red box and saw that my entire map was red. At that point I figured that either I've got a bug in my code, or something else is going on. <p> To give some context before I share what I found, a Maidenhead locator consists of a combination of letters and numbers. For four letter grid squares, there's a grand total of 32.400 different combinations, running from AA00 to RR99. They're 2 degrees wide and 1 degree high and their width depends on where on the planet they are. At the equator it's about 222 km wide and 111 km tall, at the North and South pole, it's 0 km wide. If you travel between two squares, you might have to move a meter, or the entire width of a grid square. <p> Among the report, I found stations who had activated more than one square. That's fair enough, you can move your station and start making noise where ever you like. I found stations with activations across more than a thousand different squares. Before I start pointing the finger, I will mention that if you attach a WSPR beacon to an aircraft, or a balloon, you can legitimately activate plenty of squares. <p> When you set-up a WSPR transmitter, you're required to manually enter the locator and mistakes happen. There's plenty of records with invalid Maidenhead locators, typically shown instead is a callsign. Then there are stations that pick desirable locators. This manual entry is also true for the power level and even the callsign, so I'm not outing these stations here, since it's entirely possible that the callsign shown doesn't actually relate to the transmitter or the licensed amateur. <p> What does all this mean? <p> It means that the information in the WSPR database cannot be trusted. I suspect it also means that the data used to lodge FT8 contacts across the planet can probably also not be trusted. It means that any propagation data you're deriving is likely contaminated by misreporting, deliberately or not. <p> As a community, if we want to use this for actual measurements, we'll have to figure out how to make this a trusted resource, because the information that WSPR can bring to propagation is in my opinion extremely valuable. <p> I would love to hear your thoughts on how we might fix it. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Amateur Radio and the art of getting started ...
Foundations of Amateur Radio <p> One of the regular topics of conversation in amateur radio, especially for those new to the community, is where to start? The sheer volume of available options is often overwhelming. If you've never encountered the complexity associated with this amazing hobby the experience can be disheartening and even demoralising. <p> In my early years I was results driven. Getting on air, making noise, logging a contact, adding a country, winning a contest, rinse and repeat, get better, do more. There have been numerous occasions when I came home from one of my adventures disappointed, sometimes bitterly so. <p> That happened for quite some time, until one day I realised that the journey in and of itself is the reward. <p> That might sound disingenuous, so let me illustrate. <p> This week I set-up an automatic beacon in my shack that can be heard by stations around the planet, letting me know just how far my signal can travel at any particular moment, using my own station antenna and local propagation. As projects go, it continues to be an adventure. <p> As you might recall, I like low power operation, truth be told, I love low power. The smaller, the better. Less is more and all that. I recently completed the first leg of a journey to set-up a permanent beacon. For years I'd been dabbling around the edges. On the weekend, whilst I was in my shack, I'd regularly set-up my computer and radio, set it to WSPR beacon and see what stations heard me. I couldn't turn my radio below 5 Watts, so that's what I used. Before you start, yes, I could turn down the volume, but that involves math and I wanted a result, now. <p> It filled a gap using WSPR, Weak Signal Propagation Reporter, like that. For a while, I improved on things by having a receiver set-up that monitored the bands all day every day and recently I turned it back on, with limited success, more on that shortly. <p> What I really wanted was to see where my signal was going, not what I could hear. I received a few emails suggesting that a ZachTek WSPR Desktop transmitter, built and sold by Harry, SM7PNV, would be just the ticket. It's a little metal box with USB and SMA connectors. One SMA for the supplied GPS antenna, used for location and time, the other for a transmit antenna. USB provides serial for configuration and power if it's operating in stand-alone mode. Yes, you can operate it without needing a computer and if you want it does band-hopping. After configuring it with things like your callsign and bands, you can plug-in the GPS, your antenna and power it via USB and it will run as an automatic 200 milliwatt WSPR beacon. <p> That device in turn prompted a journey to discover a more appropriate antenna, since my current station antenna uses an automatic tuner that won't get triggered by this tiny transmitter. That caused an exploration in how and where to mount any new antenna, with a side-trip into finding a specific anti-seize compound locally. To pick the mounting hardware, I had to get into wind loading, how strong my satellite dish mount might be, how to install and tune a multi-band antenna. The list just keeps growing and that voyage continues. <p> I'm tracking the requirements with a project specific check-list, just to make sure that I don't miss any steps and have a place to document new discoveries when they invariably hit me in the face. So-far, so-good. <p> The WSPR monitor receiver is currently connected to a generic telescopic dipole, mounted indoors, which in the past gave me a much better result than my station vertical, so I should be able to keep both running. <p> Next on the list is to construct a live propagation map for my station, then a way to switch modes on that map, so I can tell if it's worth calling CQ without going blue in the face. I'm also working on a WSPR transmitter for 2m and 70cm, because they are under served in my neck of the woods. <p> The takeaway from all this is that whilst there are many steps, and truth be told, that list is growing as I learn, each step is tiny and doable. The only thing that separates me from someone who doesn't know where to start, is this. <p> I started. You can too. Anywhere. Doesn't matter. Pick anything that tickles your fancy. Start digging. It's a hobby, not a profession. What ever floats your boat, what ever makes you excited, what ever you're interested in, pick it and do something, anything. <p> That's how you get anywhere in Amateur Radio, and Open Source, and life for that matter, just start. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

One Timezone To Rule Them All
Foundations of Amateur Radio <p> Right now it's 10:45. <p> That piece of information is unhelpful without any context. I could just as easily have told you that it's 2:45 and it would be just as accurate, helpful and meaningless. The point being that without context, you don't know if I'm an insomniac, drinking morning tea, recovering from a late lunch or putting on my PJs. <p> If I'm talking to people in the same room, supplying the time happens within the context of that room, but if the world is our oyster, our room is a little larger and dawn for one person is dusk for another, at the same time. <p> Before we could communicate at the speed of light and travel faster than a bullet, time was a relative thing related to the location of the Sun and considered mainly by mariners and astronomers. Even with the advent of increasingly accurate clocks, for most people, noon was when the Sun was at its highest point and the local clock was set to that. <p> When our world got smaller, because communication and travel got faster, people started noticing that noon in one place wasn't the same as noon in another place. It became a real problem when people travelled hundreds of kilometres by train in a day. Imagine coming up with a train time-table that takes into account each local version of noon. <p> In an attempt to deal with this, railroad managers in the United States established 100 railroad time zones. This malarkey continued until the 18th of November 1883 when four standard time zones were established for the continental United States. <p> Of course, being human and all, that was a local solution. Great Britain had already established its own standards for time for England, Scotland and Wales. <p> In October 1884, the International Meridian Conference, held in Washington DC, adopted a proposal that designated the Prime Meridian for longitude and timekeeping should be the one that passes through the centre of the transit instrument at the Greenwich Observatory in the United Kingdom and established Greenwich Mean Time, or GMT as the world's time standard. <p> Why Greenwich? At the time the United Kingdom had more ships and shipping using Greenwich as their reference than the rest of the world put together and the observatory at Greenwich had produced the highest quality data for a long time. As an aside, on a French map before 1911, 0 degrees was centred over Paris. There are other wrinkles, like the fact that Earth isn't round and as a result the Greenwich Prime Meridian is not quite in the right spot because measurements didn't take into account local variations in gravity. <p> In 1972, Coordinated Universal Time, or UTC replaced GMT as the standard for time in the world. It now references the International Reference Meridian, currently about a 102.5m east of the original Prime Meridian passing through Greenwich. It's on the move with reference to land because tectonic plates shift and where it is today is not where it's going to be tomorrow, so don't go looking for a marker to indicate the IRM. <p> Meanwhile in the rest of the world people needed to come to terms with how to standardise on what to call time zones. The USA establishing four time zones was just for one country. Depending on who's counting, there's over 200 countries and each has its own set of time zones. Which each might include daylight saving, or not. For some, like VK6, daylight saving was voted on several times. Trials were had and time changes during summer were implemented, then reversed, then reversed again, and again, in total, VK6 did this dance six times and we currently don't observe daylight saving, neither does VK4 or VK8. <p> So, not only does 10:45 require location context, it also requires that you know if there's daylight saving happening at that time in that location, which to add insult to injury, doesn't actually happen on the same date each year. It gets better if you consider time in another location. Do they have daylight saving, is it on at the time, do we have daylight saving at that time, how many hours are we apart, when is this actual event and what if we're coordinating efforts between people in multiple locations? Did I mention that summer in Europe is in July and in Australia it's in January? <p> In case you're wondering, tracking all this is a massive job currently under the purview of the Internet Assigned Numbers Authority. The person coordinating this, whilst wrangling the politics of naming things, including dealing with warring countries who take umbrage at having their time zone named after "the enemy" is computer scientist Paul Eggert, the project lead of the time zone database. <p> War aside, time zones are political. For example, Dublin Time was stamped out by the British as punishment for the Easter Rising. <p> If that wasn't exciting enough, to provide local context, we use abbreviations to indicate which location we're talking about. In VK6 that abbreviation is WST, simple enough, Western Standard Time. What if your abbreviation was CST? Is that Central Standard Time in North America, China Standard Time, Cuba Standard Time, or even Australian Central Standard Time. If your local time zone is IST, you could be referring to Indian Standard Time, Israel Standard time, Irish Standard Time or even Irish Summer Time. <p> As radio amateurs we hold global contests and we advertise our online club meetings and events. Often, we refer to times and dates that might be understood by an audience of one, but utterly confusing to the rest of the world. <p> So, what do you do with this? <p> Simple, use UTC. My timezone, called WST, or AWST, is UTC+8. F-troop, a weekly net for new and returning amateurs runs every Saturday morning at midnight UTC, that's 0:00 UTC. No confusion, no daylight saving, everyone can figure out if it's worth being awake for and I must applaud the amateurs from G-land and PA with their contributions in the very, very early hours of their morning. <p> So, next time you make some noise about a contest, or any amateur activity that goes beyond the people in your suburb, specify the time in UTC. Who knows, perhaps one day, even the likes of SpaceX, Apple and Google will start using UTC to announce their events ... <p> As Goldie Hawn put it: "Well, in my time zone that's all the time I have, but maybe in your time zone I haven't finished yet. So stay tuned!" <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The Rebirth of Homebrew
Foundations of Amateur Radio <p> On the 12th of December 1961, before I was born, before my parents met, the first amateur radio satellite was launched by Project OSCAR. It was a 10 kilo box, launched as the first private non-government spacecraft. OSCAR 1 was the first piggyback satellite, launched as a secondary payload taking the space of a ballast weight and managed to be heard by over 570 amateurs across 28 countries during the 22 days it was in orbit. It was launched just over four years after Sputnik 1 and was built entirely by amateurs for radio amateurs. <p> In the sixty years since we've come a long way. Today high school students are building and launching CubeSats and several groups have built satellites for less than a $1,000. OSCAR 76, the so-called "$50SAT" cost $250 in parts. It operated in orbit for 20 months. Fees for launching a 10cm cubed satellite are around $60,000 and reducing by the year. <p> If that sounds like a lot of money for the amateur community, consider that the budget for operating VK0EK, the DXpedition to Heard Island in 2016 was $550,000. Operation lasted 21 days. <p> I'm mentioning all this in the context of homebrew. Not the alcoholic version of homebrew, the radio amateur version, where you build stuff for your personal enjoyment and education. <p> For some amateurs that itch is scratched by designing and building a valve based power amplifier, for others it means building a wooden Morse key. For the members of OSCAR it's satellites. For me the itch has always been software. <p> Sitting in my bedroom in the early 1980's, eyeballs glued to the black and white TV that was connected to my very own Commodore VIC-20 was how I got properly bitten by that bug, after having been introduced to the Apple II at my high school. <p> I'm a curios person. Have always been. In my work I generally go after the new and novel and then discover six months down the track that my clients benefit from my weird sideways excursion into something or other. <p> Right now my latest diversion is the FPGA, a Field Programmable Gate Array. Started watching a new series by Digi-Key about how to use them and the experience is exhilarating. <p> One way to simply describe an FPGA is to think of it as a way to create a virtual circuit board that can be reprogrammed in the field. You don't have to go out and design a chip for a specific purpose and deal with errors, upgrades and supply chain issues, instead you use a virtual circuit and reprogram as needed. If you're not sure how powerful this is, you can program an FPGA to behave like a Motorola 65C02 microprocessor, or as a RISC CPU, or well over 200 other open source processor designs, including the 64-bit UltraSPARC T1 microprocessor. <p> I'm mentioning this because while I have a vintage HP606A valve based signal generator that I'm working on restoring to fully working. Homebrew for me involves all that the world has to offer. I don't get excited about solder and my hands and eyes are really not steady enough to manage small circuit designs, but tapping keys on a keyboard, that's something I've been doing for a long time. <p> Another thing I like about this whole upgraded view of homebrew is that we as radio amateurs are already familiar with building blocks. We likely don't design a power supply from scratch, or an amplifier, or the VFO circuit. Why improve something that has stood the test of time? In my virtual world, I too can use those building blocks. In FPGA land I can select any number of implementations of a Fourier Transform and test them all to see which one suits my purpose best. <p> In case you're wondering. My Pluto SDR is looking great as a 2m and 70cm beacon, transmitting on both bands simultaneously. It too has an FPGA on board and I'm not afraid to get my keyboard dirty trying to tease out how to best make use of that. <p> What homebrew adventures have you been up to? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Defeating the Pitfalls of Predicting HF Propagation
Foundations of Amateur Radio <p> As you might know, I like to transmit with as little power as possible, known as QRP operation. My own station runs at 5 Watts, since on HF, that's as low as my radio will go. I could go lower by turning down the microphone gain, which interestingly is how some radios actually operate, but for now, 5 Watts seems to be a good starting point and truth be told, even though I've been here for a while, I feel like I'm learning something new every day. <p> One of the largest challenges associated with using low power on HF is propagation on the HF bands which is more fluid than ever. There's plenty of variables. For example, in addition to the day-night cycle, there's Earth's magnetic field, the impact from coronal mass ejections as well as the solar cycle. As that cycle waxes and wanes, or in my case, wanes and waxes, propagation trends are affected on a longer term basis. <p> There's all manner of tools to explore this. The Australian Space Weather Service is one of many such bodies that create ionospheric prediction maps showing frequencies and their propagation through the ionosphere. Then there's the derivative ones that use this data to declare if a band is open or closed, spread widely across the globe with little in the way of context, like time, or location. <p> There are tools like VOACAP which attempt to predict the point-to-point path loss and transceiver coverage dependent on antennas, solar weather and time and date. They also attempt to arrive at a so-called MUF, the Maximum Usable Frequency, defined as the highest frequency at which ionospheric communication is possible for 50% of the days in a month. The LUF, the Lowest Usable Frequency is defined as the frequency at which communication is possible 90% of the days of the month. <p> All these tools have one thing in common. They're predictions and forecasts. They reflect an attempt at quantifying reality. There is a place for this, but my often repeated encouragement of getting on air to make some noise is advice that covers the gap between prediction and reality. <p> I've long been a fan of using Weak Signal Propagation Reporter, or WSPR as a tool to measure actual propagation. What I like most about it is that it can be used on your own station, using your own antenna, at any time. <p> It occurred to me the other day that there must be a relationship between a WSPR signal and a voice signal. Not a mathematical one, but one that makes the difference between establishing a voice contact with another station and calling CQ until you're blue in the face. <p> With that in mind I took a leap and purchased a ZachTek Desktop WSPR transmitter, capable of operating on all the HF bands that my license permits. It was shipped from Sweden this week and it is expected to take more than a month to get to me, likely most of that travelling between Sydney and Perth, but when it does, I'll be able to set up my own in-house 200 milliwatt beacon that will show me just how far my signal goes on the bands that I pick. As an aside, I'm still looking for a similar solution for 2m and 70cm since there are all manner of interesting propagation phenomena associated with those bands as well. <p> I'm still digging into how I can best gather the reception data to visualise it and I'm working on a strategy that can send me an alert when a particular band is open from my station at such a level that I can look to operating a particular mode, like FT8, or SSB, or anything that I might choose. <p> The data is public, thanks to the various WSPR reporting systems around, so others in my grid square, likely beyond that, will also be able to benefit from my beacon. I'm considering generating a propagation map from my own station and publish that, but it's too early to say what's involved in making that happen. <p> Right now I've dived into the rabbit-hole associated with finding a suitable antenna. My current station vertical requires a tuner and I don't think that finding a way to tune my antenna every time the beacon changes band is a good solution. <p> I suspect that I'll also need to come up with a way to have two transmitters share the same antenna, but I'll cross that bridge when I need to. <p> Once the beacon arrives, it's my intention to start with 10m as my beacon band using my current antenna, since 10m is on the verge of being useful for my QRP adventures and I must confess, I'm looking forward to making a voice contact with the other side of the planet with my station for the first time in a long time. <p> What kinds of things can you think of that would benefit from a solution like this? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What have you been up to in Amateur Radio lately ... Gary VK2OVA
Foundations of Amateur Radio <p> Recently I exchanged emails with fellow amateur Gary VK2OVA. This was his most recent response. <p> Hello Onno, <p> What have you been up to in amateur radio lately, you ask hahahahahahaha. <p> I hope this gives you a good chuckle. <p> I decided to construct and erect a full wave 80 meter sky loop. Simple antenna, and I have lots of space to do so with an old tennis court on the block surrounded by existing poles and wire mesh. <p> The preparation for me was the key to having an easy path to a successful outcome. First step was to measure out the existing poles for the best fit, measured, then stood back and looked, then measured again, yes all is good, this will work. Made up the ropes and pulleys, rechecked the length and height, yep all good, put the ropes and pulleys in place, ready to attach the insulators. I'm going for four corners with an overall measure of 23 meters long by 17 meters wide. Using a corner feed point. <p> Made up a feed point cockatoo deterrent, 90 mil storm water pipe about 15 inches long, split end to end, then zip tied into itself as it wraps around the insulator and feed point. Cockatoos are in abundance here so I had to come up with something to keep them away from the feed point as that seems to be their favourite chew spot. <p> Purchased a 100 meter long roll of green and yellow earth wire, thinking to myself, easy as, just cut a measured length off the end and have the correct length left on the reel ready to roll out. Oh but wait, a couple of hams talking on air had a similar situation and it worked out that the roll was shorter than quoted on the label. Best practice here is to unroll it and measure it myself, simple task. <p> Now I cannot find my 30 meter tape measure, so I put the task on hold till it turns up. Two weeks later it is no where to be seen, so now I have decided to go with the 8 meter tape measure. After thinking about how to best measure 8 meters at a time I came up with a marvellous plan, I'll put a couple pegs in the ground at 8 meters apart and simply loop the wire back and forth 11 times. After all, this is 88 meters in total and I can simply trim the length to my chosen frequency of 3.620 MHz. I'm feeling very good right about now as I have saved myself a lot of walking and bending. <p> Now, the first error pops its little head. After I've cut the wire to length and attempt to lay it out on the ground inside the poles - designated antenna holders - the copper wire reminds me it has a memory. That memory is very adamant, I'm a circle of loops. So yes I now have a birds nest of yellow and green. Have you ever noticed when something like this has a mind of its own, it is, apparently, right. Took at least an hour to unravel it, then several tent pegs, to get this wire to obey me. So I won that battle. <p> Because I had measured the wire myself I knew it to be accurate, which proved how wrong I was back when I'd completed the original measure, post to post for potential mast poles. So I reset my ropes and pulleys to the new poles and hoisted the whole lot up in the air, then ran inside to view the antenna analyser. Now something is wrong, I cannot get a meter dip anywhere on HF. Oh dear, I've got a break or bad connection. <p> So into trouble shooting mode goes whats left of my brain. Track and retrace. As much as I did I could not identify what was wrong. Only one thing for it I will go back to the beginning and start over. <p> Dropped the wire on the ground, pegged it down so it could not get away again. Still could not find my 30 meter tape measure, so out comes the 8 meter tape. But wait, is that a 6 or an 8 on there. Lets settle this, I'll put on my reading glasses just to be sure. Yep it is a 6 meter tape measure, not 8 so therefor I have only got a 66 meter length of wire, oh gosh! Back to square one, move all the pulleys re-measure everything. To correct the problem I had to add on some wire and solder the 2 pieces together. With my new level of cautious approach I managed to get the length perfect at 3.625 MHz. <p> I still cannot find my 30 meter tape, nor can I find my 8 meter tape, but the good news is I still have a 6 meter tape measure, actually out of six tape measures that I had it's the only one I can find. <p> I've decided I should probably wear my glasses when reading small print, from now on. <p> I've been making wire antennas for years and never had an issue. Having just moved here a couple of years ago I'm in a position where size does not impact my antenna choices, hence the ambitious project which took up way to much time and effort. <p> And, if this is suitable for sharing please do so. <p> Cheers, <p> Gary VK2OVA <p> <p> The only thing remaining is to ask you a question. <p> What have you been up to in Amateur Radio lately? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The Ripple Effects of making change ...
Foundations of Amateur Radio <p> During the week a new piece of software was born. It's not going to solve world hunger or address man-made climate change, but it will help some contesters who want to get on air and make noise without actually making noise. From my vk6flab github page you can get yourself a copy of a tiny little bash script with the catchy name of ssbdaemon and use it to launch your very own remote-controlled voice-keyer. <p> After making the announcement I received several emails from excited contesters who wanted to thank me for my efforts and I have to tell you, making something that others find useful is very rewarding. <p> My announcement also sparked some discussion around using voice-keyers including some who consider that this isn't a useful addition to the hobby. <p> More on that in a moment. <p> After the code was written, I had to actually, you know, use it. So I hooked up my radio, launched ssbdaemon and fired up my current contest logger of choice, TLF, and attempted to make noise. Unfortunately I wasn't so lucky as to make it all work on the first try. TLF needs to be in CW mode for ssbdaemon to work and someone, somewhere at some point, decided that when you change band, the mode needs to be set, so despite me setting my radio to either Lower or Upper Side Band, TLF would helpfully change it to CW, which actively prevented me from making noise. <p> Since TLF is Open Source, I was able to download its source-code and after some trial and error, including discussion with the TLF developer community, I added my own little flavour to my copy of TLF to make it always use sideband. My fix isn't useful long-term, but right now it will make it possible for me to operate my voice-keyer. An alternative would have been to turn off rig control. <p> This also sparked discussion on the TLF mailing list about how we might implement this kind of functionality long-term. Those two things, the fact that I could hack my own copy of TLF and discuss long-term updates is why I think that Open Source and Amateur Radio are an obvious match. <p> I released my ssbdaemon script as Open Source too, so I immediately benefited from other people looking at it and giving me feedback. As a direct result my code improved, my tool became more useful and those changes were published for anyone to use, immediately. <p> At this point I should mention that although I'm using TLF, ssbdaemon is a drop-in replacement for cwdaemon and should work anywhere as a direct replacement, so tools like CQRLOG, Xlog and others can use it with no changes to their code. <p> Back to the discussion about the usefulness of this tool in relation to our hobby. <p> I think that a tool like mine does a number of things. It achieves the direct purpose that it was built for, making it possible to create a more universal voice-keyer, but it also does other things. <p> I set out to make TLF do callsign voice-keying, but in solving the problem, I managed to build a tool that was universal to any station using an external Morse-keyer, regardless of whether or not they were using TLF. <p> Several emails commented on the way that I'd come to this solution and observed that this opened opportunities beyond my script, including operating Single Side Band contests remotely. <p> As a direct result of my release there's now a discussion underway in relation to how TLF manages band changes. It's not finished, likely it'll go through several iterations and might not be implemented immediately, but the fact that this discussion is happening comes as a side-effect of my script. <p> This little script, truthfully almost trivial script, is causing change to happen in unexpected places. <p> It did make me wonder if there are little things like this that we can do to bring awareness and activity to other areas, things like man-made climate change and how we might achieve that in tiny unexpected ways. <p> As for running a contest with my new voice-keyer, propagation permitting, keep an ear out and let me know how it goes. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How to run an SSB contest without using your voice ...
Foundations of Amateur Radio <p> As you might know, I consider myself a contester. I derive great pleasure from getting on air and making noise during a contest. It gives me a wonderful opportunity to test my station, hone my skills and work on learning something new every time I participate. <p> Due to circumstances I've been away from contesting for a number of years, but recently I was able scratch my itch from my own shack. For 24 glorious hours I was able to make contacts from the comfort of my home, being able to make a cup of tea, eat some dinner, stay warm, catch a nap when the bands were closed and generally have a blast. <p> My set-up worked well. Operating QRP or low power, I used a basic contest logger, since I wasn't expecting to be making many contacts. To automatically call CQ, I recorded my voice and set-up a script that played the audio, waited four seconds, then played it again. Using my audio mixer, I could turn that on and off at will and between that and the headset I was wearing I had loads of fun and even made contacts! <p> During the last three hours of the contest my partner came home. After hearing me attempt to confirm an exchange for a while, it became apparent that making exchanges, calling CQ and generally talking out loud was going to be an issue in our home, since my shack is within hearing range of the entire house. That or I'm going deaf and my voice is getting louder. I do get excited from time to time! <p> For the past several months I've been trying to find a solution and until today I wasn't getting any closer. <p> I didn't think I was asking for too much. <p> I'm looking for a contest logger, that runs on Linux, that has the super check partial database, knows the contest rules and most importantly, has a voice keyer with the ability to actually voice the exchange itself, as-in, not a pre-recorded audio file, but the ability to speak any callsign and any exchange. <p> As an aside, the super check partial database is a list of frequently heard contest callsigns, originally introduced by Ken K1EA, which if used properly, helps you when you're deciphering a callsign on a noisy band. Using it to guess calls and make mistakes can result in significant penalties for some contests. <p> The only tool I've come across that does all this in any way is N1MM. It runs on Windows and I have to tell you, the idea of having to buy a new computer, just to run a supported version of Windows just doesn't do it for me. N1MM also doesn't use Hamlib, so my radio needs to be physically connected to the computer. I won't bore you with my weeks of attempts, but it became farcical. <p> During my months of exploration I looked at and tried plenty of other tools. Many of them aren't intended for contesting, don't have access to the super check partial database, don't do voice-keying, don't run under Linux, require weird bits of extra software, have little or no documentation and a myriad of other issues like having to compile from source with arcane library requirements, the list goes on. <p> One contender that got close was a text only tool called TLF. It got so close that I almost used it for my previous contest. In the end I didn't because it was doing unpredictable things with the display and I had to write my own contest rule file for an unsupported contest which I couldn't test in time to actually use. <p> Today I took another look. <p> TLF doesn't have a voice-keyer on board, but it does have the ability to interface with a Morse-keyer, which is interesting, since it implies that there is a process that translates callsigns and messages typed in with a keyboard into Morse, which might mean that it may be possible to pretend to be a Morse-key and make voice sounds instead. <p> The Morse-keyer software in question is cwdaemon. It accepts text messages from TLF and then converts those into Morse code and then directly controls your radio to generate dits and dahs on-air. <p> I started digging through the source code when I realised that cwdaemon might have a debug mode that shows what it's doing. Turns out, not only does it have a debug option, you can also prevent it from keying your radio. Which means that I should be able to get TLF to generate the messages, cwdaemon to show those messages and me to do something useful, like play audio files as appropriate. <p> If I pull this off, it will mean that I can operate my station as if I'm running CW, but the radio will be transmitting voice, which makes for a beautiful way to save my vocal chords whilst running a contest without bothering anyone else and do this without needing to install Windows, which frankly, in my book is a win. <p> If I succeed, and I think the odds are good, I'll publish my efforts on my github repository for you to use, if you're so inclined. <p> I have to confess, when I started this adventure, I was not at all convinced that I could make this happen and I'd all but thrown in the towel. It still quite unbelievable to me that this kind of thing doesn't appear to exist, but if all goes well, it should soon. <p> What are you going to be doing for your next contest? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The inherent redundancy of a compromise antenna
Foundations of Amateur Radio <p> For an activity that's seeped in the art of communication, amateur radio is a diverse collection of people, joined by a common interest and kept together using imperfect language describing an intrinsically complex science in the hope that we can learn from each other to get on air and make noise. <p> In this cooperative endeavour, language is important. <p> Let me start with a limerick by Arthur Frackenpohl: <p> There was a young fellow of Perth Who was born on the day of his birth He married, they say On his wife's wedding day And died when he quitted the earth <p> Stay with me. <p> In this day and age, first and foremost, let me give you a short summary, cobbled together from bits and pieces of a new invention, conceived whilst watching the evening sunset in close proximity to the beach. <p> What this cornucopia of tautologies has to do with our hobby might not be obvious, but let me illustrate. <p> Consider the phrase: "a compromise antenna", as-in, "Oh, I'd never use that antenna, it's a compromise antenna." <p> If you've been in this community for any time at all, you'll have heard that phrase and unless someone pointed it out, you might not have realised that it's essentially unhelpful. <p> Why? <p> Because as I've said many times before, all antennas are a compromise, by definition. This is true at several levels. <p> At a fundamental level, an isotropic antenna is a theoretical antenna that radiates equally in all directions - horizontally and vertically with the same intensity. It's infinitely small and operates on all frequencies with infinite bandwidth. It should be obvious, but this antenna cannot physically exist, so every built antenna represents a collection of trade-offs or compromises and no antenna can radiate more total power than an isotropic antenna. <p> Beyond that, within the physical constraints of antenna building there are many more compromises. Now this might not be immediately obvious, so let me elaborate. <p> Consider a 28 MHz, seven element Yagi antenna. With a 12m boom, a 5.3m reflector element, a turning circle of 7.5m and weighing in at 53 kilo. At 20m above the ground it has a gain of 17.5 dBi and handles 1.5 kW. It's physically capable of withstanding 180 km/h winds. It's a lovely piece of kit and if you have the space, it's absolutely something you might want to receive for your birthday and bolt to a mast somewhere near your radio. <p> If all antennas are a compromise, you might ask yourself, how is this beautiful 10m Yagi a compromise? <p> For starters, its total radiated power is less than an isotropic antenna. It works between 28 and 29 MHz, but nowhere else. It radiates signals really well in one direction, but not in any other. It requires lots of open space and as a fixed installation, it must be on a heavy duty rotator clamped to a tall mast. To actually acquire and install requires more funds than I've spent on all my radios to date. <p> Some of what I've mentioned might be acceptable to you, some not. For example, if you're always portable, this antenna makes no sense. You make choices to select an antenna that's best suited to the job and in doing so, you are introducing compromises. <p> Additionally, there are amateurs who would have you believe that a compromise antenna is one with high loss. <p> High loss in comparison to what? <p> If you live in an apartment block, there's no way that you can fit that 10m Yagi inside your bedroom, so you compromise and use a magnetic loop antenna instead. If you're on the top of a mountain, there's no opportunity to erect a structure, so you use a self-supporting vertical. If you're in a car, you cannot erect a horizontal dipole and drive down the highway, so you bolt a whip to your jalopy. <p> All of the choices you make to fit a purpose, an environment, a budget and available material will combine into an antenna that hopefully gets you on air making noise. <p> When someone tells you that an antenna is a compromise antenna, what they're really saying is that you made compromises that they're unwilling to make. That's easy to say if you have infinite space, money, experience and opportunity. In other words, they're just blowing hot air. <p> The whole point of antenna building is to find a particular set of compromises that suits your situation at the time that you're doing it. The intent of this hobby is to learn what the impact of a particular choice is and how it affects the operation of an antenna in a specific situation. <p> Next time you hear the redundant phrase "that's a compromise antenna", ask what compromises they are describing that they don't accept and decide for yourself if they are compatible with what you're attempting to achieve within the resources available to you. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Standard Information Exchange in Amateur Radio
Foundations of Amateur Radio <p> The art of storing information in such a way that it doesn't devolve into random gibberish is an ongoing battle in the evolution of the human race. Egyptians five thousand years ago were perfectly happy storing information using hieroglyphs. They used it for well over three thousand years, but today you'd be hard pressed bumping into anyone on the street who knows one, let alone one thousand characters. <p> Latin fared a little better. It's been in use for over two thousand years, but other than fields like biology, medicine and of course some religions, the best you can hope for is et cetera, mea culpa and my favourite, carpe noctum, that and a few mottos scattered about. <p> Using technology to store information is no better. If you have a 3.5 inch floppy disc tucked away in a drawer, can you still read it today and do you know why it's called a floppy disc? What about a 5.25 inch, or 8 inch floppy. What about tape. Do you still have backups stored on DAT? <p> Even if you could physically read the information, could you still make sense of it? Can you open a VisiCalc spreadsheet file today? That was invented during my lifetime, first released in 1979. The latest release was in 1983. <p> My point being that storing and retrieving information is hard. <p> Amateur Radio is an activity that has been around since the early 1900's, over a century of information. We describe our collective wisdom in books, magazines, audio recordings, websites, podcasts, videos and tweets. <p> One of the more consistent sources of information coming from our activity is logging, specifically QSO or contact logging. There are bookshelves full of paper log files, but since the advent of home computing, logging now is primarily an electronic affair. <p> If you've upgraded the software on your computer, you know the pains associated with maintaining your log across those transitions. If you've changed operating systems, the problem only got worse. <p> Currently there are primarily two standards associated with logging, the ADIF and Cabrillo specifications. Both are published ways of describing how to store information in such a way that various bits of software can read the information and arrive at the same interpretation. <p> As you might expect, things change over time and any standard needs to be able to adopt changes as they occur. How that happens is less than transparent and in an open community like amateur radio, that's a problem. <p> Used primarily for logging contacts, the Amateur Data Interchange Format or ADIF is published on a website, adif.org. There's lively discussion in a mailing list and since its inception in 1996, it's evolved through many versions, incorporating change as it happens. Like the adoption of new digital modes, new country codes and administrative subdivisions. <p> Used for contest logging, Cabrillo is published on the World Wide Radio Operators Foundation, or WWROF web site which assumed administration for the specification in 2014. It documents changes as they occurred, like adding contest names, station types and contest overlays. While there's clearly activity happening, there doesn't appear to be a public forum where this is discussed. <p> Speaking of public. <p> The DXCC, or DX Century Club is a radio award for working countries on a list. ADIF stores those country codes using the DXCC country code number, which is part of the specification published by the ARRL, the American Radio Relay League. The list of DXCC entities is copyrighted by the ARRL, which is fair enough, but you have to actually buy it from the ARRL to get a copy. This is a problem because it means that any future archivist, you included, needs access to a specific version of both the ADIF and the then valid DXCC list, just to read the information in a log file. To put it mildly, in my opinion, that's bonkers. <p> Relying on external information isn't limited to ADIF. Cabrillo relies on external data for the format of the Location field which indicates where the station was operating from. Among others, it refers to the RSGB, the Radio Society of Great Britain who maintains a list of IOTA, or Islands on the Air, published on a web site that no longer exists. <p> There are other issues. <p> It appears that for the Cabrillo specification there is no incremental version number associated with any changes. Version 3 of Cabrillo was released in 2006. There are 31 changes published to update Version 3, but as far as I can tell, they're all called Version 3, so anyone attempting to read a Version 3 log will not actually know what they're dealing with. To give you a specific example of three changes. In 2016 the 119G band name was changed to 123G, which was changed in 2021 to 122G. All three labels refer to the same band, but until you actually start looking at the file will you have any indication about the version used to generate the file. <p> Let's move on. <p> Contesting. Not the logging or the on-air activity, but how to score a contest. What activity gets points and what incurs a penalty? Do you get different points for different bands, for different station prefixes, for low power, for multiple operators, for being portable and plenty more. Can you make contact with the same station more than once, if so, how often and under which circumstances? What is the exchange, how does it change, if at all? Each of these choices are weighed by contest managers all over the globe and they do it every time they run their contest. For some contests that means that there are dozens of rule versions across the years. To give you some idea of scale, the modern CQWW was first run in 1948 and there's at least one amateur contest every weekend. <p> Now imagine that you're writing contest logging software that keeps track of your score and alerts you if the contact you're about to make is valid or not, or if it incurs a penalty if you were to log it. That software is driven by the rules that govern a particular contest. <p> Some contest software is updated by the author every time a major contest is held to incorporate the latest changes. Other contest tools use external definition files, which specify how a particular contest is scored. <p> As you might suspect, that too is information and it too is in flux and to make matters worse, there is no standard. So far, the tools that I've found that make any concerted attempt at this all use different file formats to specify how a contest is scored and of those, one explicitly points out that their file format doesn't incorporate all of the possible variation, leaving it to updating the software itself in order to incorporate changes that aren't covered by their own file format. That is sub-optimal to say the least. <p> Personally, I think that there is a place for a global standards body for amateur radio, one that coordinates all these efforts, one that has a lively discussion, one that uses modern tools to publish its specifications and one that does this using public information with an eye on record keeping. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

You in the community ...
Foundations of Amateur Radio <p> The other day a member of our community proudly showed off their plaque for first place as a Short Wave Listener or SWL in the Poland SP DX Contest. Together with their dad they listened on 80m using a WebSDR and logged all the contacts they were able to hear. Their participation didn't include transmitters, since neither have got their callsigns, yet. <p> To me this illustrates exactly what it's like to dip your toes into the world of amateur radio and it's a path that many amateurs have taken to become licensed and transmitting. <p> I'm mentioning this because that same short wave listener also won a platinum diploma from the anniversary of Stanislaw Lem's 100th birthday amateur contest. <p> If that name sends tingles of excitement down your spine, you're familiar with his work. If not, you might be interested to know that Stanislaw Lem was a world acclaimed Polish writer of science fiction who died in 2006. <p> This random discovery, in addition to giving me ideas about opportunities for contests and awards, reminded me of other times when in one setting I've been surprised by information relating to another setting. In this case, science fiction. In previous workplaces I've come across software developers, technicians and managers who outside their roles in computing were active as volunteer fire-fighters, paramedics, writers, stage performers, singers, foster parents and more. <p> It occurred to me that we in the amateur radio community spend most, if not all, of our time discussing amateur radio, but that we likely share other interests with our community. I recently discovered other science fiction nerds, a cos-player, there's some volunteer fire-fighters and the like, no doubt there's more. <p> My point being that in addition to finding more common ground between us as a community, we also have the opportunity to share our hobby with other people who share our interests. It's hard to imagine that science fiction fans and fire-fighters for example are unable to relate to amateur radio. <p> Don't get me wrong. I'm not advocating that you hit the members of your other communities over the back of the head with amateur radio. Instead, think of it as another way to connect to that group. <p> The thing that strikes me about our amateur community is the diversity that it encompasses. It means that there's likely plenty of other interests that you will find that bind you to other amateurs and it likely means that your other hobbies and interests might share some of your amateur interests. <p> Truth be told, as all consuming as amateur radio is, it's not the only thing that defines you and it's not the only thing of interest to the people around you. <p> What those interests are is up to you. <p> Only one way to find out. <p> Talk with your friends. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The sun shines on our hobby in unexpected ways.
Foundations of Amateur Radio <p> When you begin your amateur radio journey, one of the first things you learn about that's not directly involved with radios and antennas is the ionosphere and its impact on long distance communications. Immediately after that you are more likely that not to be introduced to the biggest plasma experiment in our backyard, the Sun. <p> With that introduction comes information about solar flares, solar flux, sunspots, geomagnetic storms, coronal mass ejections as well as the solar cycle, the solar index and associated propagation forecasts. <p> Before I dig further, I will point out that I'm mentioning this with the ultimate aim for you to get on air and make noise, so fasten your seat-belt and let's go for a ride. <p> The Sun is big. If it was hollow, it could fit more than a million Earths inside. The Sun accounts for 99.8% of the total mass of our entire solar system. About 73% of the Sun's mass is hydrogen, about 25% is helium and the rest, about 1.69% is made up of all the other heavier elements, both gasses and metals, which add up to around 5628 times the mass of Earth. <p> The Sun rotates. Counter-clockwise. Since it's mostly plasma, it doesn't rotate like Earth does. The equator takes about 24 days, the poles around 35 days and because its rotating on an angle of about 7.25 degrees from Earth's rotation axis, we get to see more of the solar north pole in September and more of the solar south pole in March. <p> Earth orbits the Sun in a year, but it's not a circular orbit. We're closest to the Sun in December and furthest from the Sun in June. It takes about eight minutes and 19 seconds for a photon leaving the Sun to reach Earth, but that same photon can take between 40,000 and 170,000 years to travel from the core where two atoms were heated and compressed to fuse into a new element releasing a photon and heat. It takes this long because the photon keeps bumping into other atoms along the way. While we're at it, consuming about 4 million tons of hydrogen per second, the Sun will take another 5 billion years to consume all the available hydrogen. <p> Whilst we experience the Sun as a source of light on a daily basis, as a radio amateur you know that light is just one tiny part of the electromagnetic spectrum. It should come as no surprise that the Sun is radiating across all frequencies all the time, only some of which is visible to our naked eye. <p> As an aside, it's interesting to note that our eyes are essentially translating light into electricity, or said differently, your eye converts radio spectrum into electricity, something which your radio antenna also does. <p> Back to the Sun. <p> I'm highlighting this level of solar complexity because there's so much talk about the A index, the K index, the SFI, the solar cycle and propagation by experts and amateurs that it's easy to hide behind those numbers and think that a low A between 1 and 6, a low K of 0 or 1 with an SFI above 100 will give you the propagation you're looking for. <p> If you think for a moment that the weather forecaster has a difficult job accurately telling you if you need to postpone your outdoor activation because of rain or snow, then you can begin to understand just how complex the interplay between the Sun and our ionosphere is. And I haven't even mentioned that the ionosphere isn't static either. <p> It's important to remember that the cute little weather icons you see on the TV news are just as much an indicator of expected weather as the A, K and SFI numbers are for the Sun and its impact on radio propagation. They give you an idea of what might happen, but it doesn't mean that on any given day something completely random and isolated happens that just affects your station and the path that a radio signal took from your antenna to that other rare DX station. <p> Just like it would be smart to take an umbrella with you when there's rain forecast, it's also smart to consider the bands you want to operate next time you go on air with a particular solar forecast, but just because it might rain, doesn't mean you're guaranteed to get wet. <p> So, in other words, wait for it, get on air and make some noise! <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

We need more glue in our hobby ...
Foundations of Amateur Radio <p> Since December 2010 I've been licensed as a radio amateur. For some this seems like a long time ago, for others, it's just the beginning. In my time thus far I've attempted to document and describe my journey and in doing so, I've had the unbeatable pleasure of hearing stories from others who were inspired by my efforts to join, or rejoin the hobby. <p> It occurred to me that it's hard to tell when you look at any one amateur if the ink on their licence is still wet, or if the whole certificate is faded and yellowed with time. <p> You also cannot tell by looking if one amateur turns on their gear in the car during the daily commute, or if they go out on expeditions to remote locations twice a year. <p> The callsign a person holds tells you even less, let alone the class of their license. <p> In our community we talk about mentoring and we call such people Elmers, but do we really use this as a way to glue together our hobby as its namesake might suggest? <p> As a result of my profile, there's a steady stream of commentary about what I do and how I do it. As you might expect, there's both good and bad, sometimes describing the same thing from opposite sides in equally heated terms. <p> I'd like to take this opportunity to point out that playing the man and not the ball will get you completely ignored. If however you have a specific grievance with any technical aspect of what I'm contributing, by all means let me know, but be prepared to provide references because it might come as a surprise, I do research before I open my mouth. That's not to say that I don't make mistakes, I'm sure I do and have. <p> Before this turns into a self congratulatory oration, I'd like to point out that all the negative feedback I see all around me does nothing to grow our hobby, does nothing to encourage learning, does nothing to reward trial and error and it doesn't contribute to society at large in any way. <p> I'm mentioning this because I also receive emails from amateurs who have left the community, not because of lack of interest, but because of the bullying that they've experienced. <p> I know that there are several local activities that I avoid because it's just not fun to bump into people who are friendly to your face whilst being vicious online. <p> It continues to amaze me that this topic keeps recurring and that it keeps needing to be called out. One thing I can tell you is that ignoring it doesn't work. I've described previously what you should do instead when you're the subject of such petulant behaviour, but it bears repeating. Say it out loud. <p> "Thank you for your comment. I don't believe that it's in the spirit of amateur radio. Please stop." <p> Feel free to use that phrase anytime someone in this hobby makes you feel uncomfortable. <p> One final observation. If you've not personally experienced this behaviour that's great, but it doesn't mean that it doesn't happen or that it's not endemic. Consider for a moment how you'd feel if you were attacked whilst being active in a hobby you love, for no other reason than that the person attacking you didn't like the wire you were using to construct a dipole or some other equally outrageous reason like your gender, sexual orientation, license class, choice of radio or preferred on-air activity. <p> Say it with me: <p> "Thank you for your comment. I don't believe that it's in the spirit of amateur radio. Please stop." <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The Fox Mike Hotel Portable Operations Challenge
Foundations of Amateur Radio <p> Getting on air and making noise is what it's all about, so last week, that's exactly what we did. Randall VK6WR, Jishnu VK6JN and I participated in the Fox Mike Hotel Portable Operations Challenge which is specifically scored to deal with power and mode differences between stations by using a handicap system that they liken to playing golf. Having been the winner of the Sir Donald Bradman Award in the Millmerran Memorial Golf Tournament for making the highest score on the day, this speaks to me in more ways than I can say. In case you're wondering, more hits in golf is bad and I'm not a golfer. <p> Scoring in the Portable Ops Challenge is based around four different attributes, the power you're using, the nature of your station, portable or fixed, the mode used and the number of transmitters in use. <p> To achieve this, you exchange a maidenhead grid square, a combination of letters and numbers that indicates your location on earth, which is then used to determine how many kilometres per Watt are used to make the contact. <p> If you're portable, you get a multiplier benefit in the scoring. <p> Depending on the perceived difficulty of the contact, you score more points. In this case, SSB is harder than CW, which in turn is harder than a digital mode. <p> Finally, the more transmitters you have, the less each contact is worth. Two transmitters, means you score half the points for each. <p> With that in mind, a QRP portable station with a single transmitter calling CQ on SSB is the best way to make points and that is something that I'm always up for. <p> In our adventure, we opted for a slight change, instead using FT4 and FT8, using 40 Watts, portable, on the side of a hill in a local park and during the four hours we were active, we managed six contacts, one over SSB, the rest using digital modes and we all had several goes at getting the best out of our station. <p> Our set-up consisted of a small folding table next to my car with a computer, a radio and a thermos flask with hot tea to ward off the chill in the air. Power was supplied by an 80 AH battery. The radio was an Icom IC-7300 that Randall brought along. <p> The antenna we used was a Terlin Outbacker, multi-tap whip that was attached to my car with a 12m counterpoise run along the gutter. <p> None of us had ever seen such excellent conditions with such a low noise floor in the middle of the city. We were enjoying the last warm sun of the day from Kings Park in Perth, Western Australia. It's a 990 acre park, larger than Central Park in New York, set aside for public use in 1831 and gazetted as a public park in 1872. The park is open 24 hours a day and features a botanic garden with thousands of species of Western Australia's native flora and fauna, overlooks the central business district, the Swan River and the Darling Ranges and best of all, there's no radio noise. It did get chilly towards the end, but I'm pretty sure we all went home with all our fingers and toes intact. <p> Jishnu also brought along his FT-817 and a tiny multi-tap telescopic whip that we strapped to a nearby steel rubbish bin and using that set-up was able to detect and transmit WSPR signals across the globe as part of experimentation with his station. <p> One of the unexpected benefits of not yelling CQ into a microphone ad-nauseam was that we were able to continue our conversation, hearing stories from each other and enjoying hot pizza when dinnertime came around without needing to stuff food into the same place where CQ calls were intended to originate. <p> My car isn't quite ready to go completely portable, but this little outing again proved to me that portable vehicle based operation has a charm all its own and the Fox Mike Hotel Portable Operations Challenge is going to be on my dance card next time it comes around! <p> When was the last time you left your shack and went portable? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What's in a sound?
Foundations of Amateur Radio <p> Over the past few weeks I've been having my hearing tested. I've had the opportunity to discuss sound in some detail with an audiologist. Today as a result of a collision between a jar of chilli pickles and a tiled floor I've come to the realisation that sound is important in unexpected ways. <p> It will probably not come as a surprise to you that sound has an emotional component. Just think of a particular song, or a voice, or something that you've heard previously. The sound of a jack-hammer, or a bell, a horse or a jet, each completely different, impact on your mood. Some sounds are pleasant, others jarring. Some make you feel happy, others make you anxious or even angry. <p> For some time now I've observed in myself that there are times when I cannot stand sound and other times when I invite it into my life. <p> For example, if there's a HF radio going in the background and I'm attempting to have a conversation with a person in the shack, the sound coming from the radio causes irritation, to the point of needing to turn it off in order to actually hold a conversation. On the other hand, if there's a contest on, I can sit, happy as a clam, listening to HF all day and night, working out what station is calling, and making contact. <p> I'm raising this because it occurs to me that amateur radio is unlike broadcast radio where you're expected to actively monitor what is being transmitted. In my experience as a radio broadcaster you're talking into a microphone and the headphones you're wearing are connected to a radio receiver which is tuned to the station on which you're broadcasting. This gives you immediate live feedback on the state of your audio levels. <p> As an aside, I once witnessed a fellow broadcaster who didn't feel the need to wear headphones. They were blissfully unaware that their voice was being transmitted into silence because the audio fader on their microphone was down. <p> In amateur radio however, we don't often do such things. We transmit blind most if not all of the time. It's rare that we even hear our own voice on-air, let alone hear it in real time. If that's not enough, using sideband, it's easy to modify the sound of a person by changing the frequency slightly, making their voice either higher or lower, just by adjusting the dial. <p> It occurred to me that how your voice is perceived by the other station assists in how that station can hear you and make contact. <p> Using the local repeater is a good but subtle example. If you've listened for a while, you might have observed that there are stations that are easy to understand and others that are not. Sometimes that comes down to individual accents, but in my experience a much larger impact is caused by the actual transmission itself. <p> Is the microphone gain set correctly, is there any filtering in play, is the station on the correct frequency, is the transmitter using the correct mode and other more subtle things like background noise, speaking volume and distance and direction in relation to the microphone. <p> We often talk about less being more and you already know that I'm a big fan of low power or QRP operation. Making contacts is absolutely about using the right antenna, the right mode, the correct band and time of day, but the sound coming from your station is just as important. <p> If you have the ability to use two radios simultaneously, then I'd recommend that you find a way to either use a local repeater, or a cross-band repeater, or even a remote web-based radio, to hear what you actually sound like on-air, live, and experiment with the various settings on your radio in order to test and improve the quality of your voice. <p> Whilst we as radio amateurs don't standardise our signals, though personally I think it would be a great idea, there's plenty of improvement to be had by taking some time out of your next on-air activity to have a long hard listen to yourself. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Taking your shack mobile
Foundations of Amateur Radio <p> When I first started in this hobby I found myself surrounded by other amateurs who all seemed to have a spare room in their house, or a spare building near their house, or even a property somewhere, dedicated to amateur radio. There was an endless parade of equipment, antennas, tools, workshops, spare parts and the like. Frankly it was overwhelming. <p> A decade on, I have some perspective to share on that first exposure. For me the hobby was brand new. I didn't have a family history, there were no amateur friends I'd grown up with, no electronics uncle or anything even remotely resembling any of that. What I was exposed to wasn't a new thing, it represented something that had been going on for years, decades and lifetimes even. <p> It quickly became apparent that having a shack was desirable, but in my case, at the time, unobtainable, so instead I did the next best thing I could think of. I built a shack in my car. That was a journey that took several years to make. At the end of it, I removed my radio from the car and moved it onto a spare table in my office. <p> I have spent countless enjoyable and sometimes frustrating hours in my car shack and I learnt that it's almost always temporary. If you're not the exclusive user of the car, then your shack isn't always available and in that case it also needs to be family friendly, as-in, no cables, mounts, brackets and the like that can cause damage to a person, or the equipment. This limits the options you have. <p> At the end of my car journey, I had a spare battery in the back, the radio and tuner were mounted under the floor next to the spare tyre, there was an antenna mount attached to the car, there was braiding throughout the car, connecting all the body panels together and the remote control head was detachable from a suction mount that doubled as a mobile phone holder. Antennas, one for HF, one for VHF were stowed against the roof lining with a strap around the roof hand grab of the rear passenger. An external speaker was mounted below the head rest of the centre rear passenger. <p> What I learnt was that this setup was good for short stints, for mobile operation, for contests on the run and for working DX at lunch time at the beach. Trying to do digital modes, attempting to work a pile-up, or doing several other activities I love were not really feasible and as a result I decided to pull it all out. <p> At this point all that remains in the car are the braiding, the control lead, the speaker, the coax and the antenna mount. I plan to rebuild my car shack in the not too distant future. More on that in a moment. <p> I moved house and found myself in an office that was perfect for multiple reasons. It was separate from the rest of the living space, so I didn't need to put away stuff. It was big enough to house a dedicated radio table and it's got pretty simple access to the outside world for running coax. It gives me a dedicated place to do radio and have stuff set-up permanently. <p> I noticed one thing after having this available. <p> I didn't actually get on-air any more than when I was using my car shack. If anything it's less. I think it's because it's also my office and I already spend plenty of time doing office activities that playing radio isn't all that different. I'm going to keep my set-up, but I'm going to go back to my roots and add a radio back into my car. <p> It's still a family car, so I need to consider the other uses that it's put to, but I think I can make it work. I recently installed an 80 Amp Hour battery with an automatic charging circuit. It was put there to power the dash-cams, but it was scaled with amateur radio in mind. <p> I don't yet know which radio I'm going to put into the car, I really do like my FT-857d, but there are other options available to me, so I'm going to experiment. <p> One fundamental change I'm going to make is that the radio will be installed in such a way that it can be easily unplugged and removed. Not because I want to remove it from the car, but because I want to be able to go even lighter, take the radio onto the beach, or into a park or up a summit. I'll likely bolt the whole lot into a Pelican case and make it a mobile go-unit that happens to live in my car. <p> I don't think I'll add digital functionality at first, but I'm eyeing off the idea of dedicating an old mobile phone, which is essentially a computer, screen, battery and internet connection in one to the task, but I'll let you know how that goes. <p> What I do know, with hindsight, is that less is more. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What's in a unit?
Foundations of Amateur Radio <p> In our hobby we use kilohertz and megahertz enthusiastically. Sometimes even gigahertz. The other day during a discussion the question arose, what comes after tera, as in terahertz? I couldn't remember, so I had to look it up, peta comes next, then exa, zetta and yotta, derived from the Greek word for eight. <p> That in and of itself was interesting, but it turns out that Greek isn't the only language used in attributing SI metric prefixes, SI being the International System of Units. Of the 20 units, which I'll get to in a moment, there's 12 with Greek origins, five deriving from Latin, two from Danish and one from Spanish. <p> The units are used to describe how many of a thing there are in base-10, so, a thousand of something is kilo, or ten to the power of three, which gives us kilohertz. A gigahertz is ten to the power of nine and so-on. Interestingly, kilo is derived from the Greek word thousand, but mega comes from the Greek for great. Both hecto, as in hectopascals and deca as in decathlon originate in the Greek words for hundred and ten. The prefix pico, as in picofarad comes from the Spanish word peak and femto as in femtowatt comes from the Danish for fifteen, as in ten to the power of minus 15. Apparently a zeptomole of a substance contains 602 particles, even NASA says so, let me know if you can find a source for that. <p> I could devote my entire discussion on these 20 units, adding for example that their naming wasn't all done at the same time, the most recent additions are yotta and yocto, as I said, derived from the Greek for eight, being ten to the power of 24. How's that eight you ask? Well, three times eight is 24. I'm not saying it's intuitive, but there is logic. <p> In looking at all these units, and specifically the smaller ones, milli, micro, nano, pico and the like, it occurred to me, is there a way to go below one Hertz, could you have half a Hertz? <p> Hertz is the number of oscillations per second, a single Hertz being one per second. Half a Hertz would be one oscillation per two seconds. I started wondering what to look for in discovering if anyone has been playing with this. For the life of me, I couldn't think of what to search for and my experience tells me that if you cannot find the answer online, you're asking the wrong question. <p> This morning, with a fresh cup of coffee in my hands, it occurred to me that anyone doing this kind of stuff would be using SI units, so they'd be using decihertz, centihertz, millihertz, microhertz and nanohertz, perhaps even picohertz. So I went searching. <p> Turns out that this actually exists. After wading through endless results with conversion tools and dictionaries, there's plenty of research to find. <p> The unit decihertz is being used in gravitational wave interferometry, specifically, there's a Japanese, space-based gravitational wave observatory in the works with hopes of launching their three space craft if they can find funding. <p> It doesn't end there. <p> There are experimental imaging studies being made on malignant and benign human cancer cells and tissues looking at decihertz all the way down to yoctohertz, that's ten to the minus 24. <p> Inside Apple software development documentation, in addition to mega, giga and terahertz you can find links to milli, micro and nanohertz as predefined units. <p> NANOGrav stands for North American Nanohertz Observatory for Gravitational Waves and it uses the Galaxy to detect them. It was founded in 2007 and is part of a global community of scientists in places like Australia, where the Parkes Pulsar Timing Array is located - yes, that Parkes - made famous from the film "the Dish" and Europe with the European Pulsar Timing Array, combining five separate radio-telescopes, all coming together under the banner of the IPTA or International Pulsar Timing Array. <p> The point of my little exploration is that if you're curious about random things, you can often come across activities and ideas you know nothing about and learn something along the way. <p> Today I learnt that there is such a thing as a sub-Hertz signal, it's being explored all over the globe with scientists in different fields and it's happening without much in the way of public awareness. <p> What did you learn today and which SI prefix didn't I use? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Being an equipment custodian
Foundations of Amateur Radio <p> A couple of weeks ago an amateur put out a call on the local email discussion list. The message was simple, it read: "I have a 606A HP Signal Generator with a copy of the Operating and Service Manual. It covers 50 kHz to 65 MHz. Free to a good home :-)" <p> It's not the first time that such a message has done the rounds, but this time my reply was quick enough for it to be first. Overnight I became the new custodian of a Hewlett Packard 606A Signal Generator. <p> A signal generator is a tool that can form a specific carrier across a range of frequencies in much the same way that your amateur radio can. In this case, the HP-606A can cover all the amateur HF bands and everything in between. The signal that's generated is calibrated, that is, it's of a specific power level, very stable, clean and it can be used to calibrate other equipment. <p> To set the scene, the HP-606A was released into the wild in 1959. You might call it vintage at this point. It's the size of a modern microwave oven, so I'll need to set aside some bench space in order to actually use it. According to some it's "the best analogue signal generator ever built". It's been in production for decades, with plenty of information to be found online. <p> Unlike most modern gear, this equipment comes fully documented by the manufacturer, to the point of user manual revisions depending on the serial number and including essentials like circuit diagrams, parts list, spare parts list, calibration instructions and the equipment needed, how to open it up, tests to conduct after repair, how to conduct regular maintenance and how to replace the tubes in it. <p> Yes, I did say tubes, or valves, or glow in the dark electronics. <p> At this point I've not yet switched it on. You might wonder why that's the case. This unit has internal voltages exceeding 500 Volt DC, so some care is required. Inside are at least four electrolytic capacitors. Think of each of them as two pieces of aluminium sandwiched together, separated by a piece of foil and electrolytic paste, all rolled up into a cylinder. <p> When an electrolytic capacitor is built, the process to convert these components into an actual capacitor involves forming it, which means that the manufacturer applies a specific voltage to the pins of the capacitor and in doing so, causes a chemical reaction which makes all manner of funky stuff happen, including unidirectional conductance, something you're looking for in a capacitor. <p> Over time, when not in use, or in my case, in storage, this chemical reaction reverses and the capacitors are back to rolled up aluminium with some foil in between. Powering it up in this state will let the smoke out. <p> It turns out that in many cases you can apply the voltage again and reform the capacitor. Apparently, according to the author of Tu-Be Or Not Tu-Be Modification Manual by H.I. Eisenson, applying the voltage for five minutes plus one minute per month of storage does the trick. In my case, I can leave the capacitors in circuit and apply the voltage externally using a Variac, a Variable AC Transformer, loaned to me by Denis VK6AKR. <p> Doing the math is a little tricky, since we don't really know when the unit was last powered up, but we're told that it was some time in the last decade, so a couple of hours should suffice, but there are some wrinkles in relation to voltage and managing the step to powering up the tubes, so when I've made it happen, I'll let you know. <p> Denis was kind enough to help with opening up the cabinet and having a look-see inside. We noticed that it has previously been expertly repaired with a few replaced components and Denis managed to identify some likely failed tubes, so we're on the scrounge for those. Together we did some initial tests and ran up the unit using low voltage to determine if the various test points were actually showing the proportional voltages that were expected. This isn't like a digital circuit where it either works or not, using a Variac, you can slowly power this up, to a point, and test along the way. <p> This brings us to the provenance of this tool. <p> I got it from Dave VK6AI and from discussion, we think it came from the estate of Don VK6HK, now silent key. I've met Don's widow who happens to be the neighbour of a friend, so at some point when I have it working I might give her a call. I don't know who owned it before Don. I do know that when it was released, in 1959, it was sold for $1540 US Dollars, the equivalent of $14,000 in today's money, or half a car back then. <p> Based on serial numbers, this HP-606A appears to have been manufactured between October 1961 and August 1966, so it's older than I am. In case you have extra information, the serial number is 009-01180 and my email address is cq@vk6flab.com. If you have spare valves, a 12B4A is high on the list, get in touch. <p> While Denis and I were exploring inside the guts of this function generator, we were at the clubhouse of the local WA VHF Group, surrounded by other amateurs who were doing their own thing. At one point I looked up and noticed two amateurs in deep discussion about using a piece of software, CHIRP, to program a handheld radio on a Windows 10 laptop, whilst I was sitting across the table, picking through the guts of a 1960's piece of equipment. It made me smile, thinking about the history that those two extremes represented. <p> Becoming the custodian for such a significant piece of equipment isn't for everyone. I've been given suggestions to toss it out and buy something modern, but I have to confess, even though I'm software personified, SDR to the core, well, aiming to be, this piece of equipment does something for me. <p> What equipment do you own that makes you go all misty eyed? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

All the things that aren't amateur radio...
Foundations of Amateur Radio <p> Recently I illustrated the diversity of our community by highlighting social media posts made to a single community over a 24 hour period. Each reflecting a different aspect of our community. <p> It occurred to me that although those things are amateur radio, some more obviously than others, there's a whole other side of the community that isn't amateur radio. <p> Look at radio astronomy for example. One of my friends is an astronomer and we've been having loads of fun learning from each other. I'm getting exposed to concepts like Fourier transforms, interferometry, sampling and plenty of the mathematical concepts that underlie my interest in amateur radio. <p> Then there's things like physics. While I've always been interested, long before I met my physics teacher in high-school who helped me kick off a career in computing, I've been playing with light bulbs, batteries, disassembling old hardware like the valve radio that I was given when I was about twelve or so. <p> There's the continued curiosity about audio. I've been making mix-tapes since I was nine, and that has blossomed into an ongoing interest in audio production, some of which is reflected in my weekly podcast and fuelled by my hearing loss. <p> My interests outside amateur radio have always been wide and varied. I've learnt to fly an aeroplane, learnt to navigate a sailboat, learnt to drive a truck, installed satellite dishes in the bush and built a mobile satellite ground station, built software solutions for piggeries and bakeries, provided logistics for remote outback events, built vehicle mounted GPS tracking and mapping solutions and I continue to read articles as they come my way. <p> What amateur radio has given me is a context, a framework if you like to bring together these wide ranging fields and make them hang together. <p> An obvious, though simple example, is learning the phonetic alphabet. In amateur radio it's a given that you'll need to learn that so you can effectively communicate using a poor signal path, but my phonetic learning predates my amateur radio exposure by at least a dozen years. In order to pass my aviation radio certificate, I was required to learn the phonetic alphabet before I was allowed to use the radio. <p> It's only a small example, but it's illustrative on how, for me at least, amateur radio is the glue that binds it all together. <p> It happens at other levels too. I've mentioned in the past that looking at a television antenna on the roof of any house before getting a license was a non-event. Today I can't look without thinking about propagation, how the antenna is aligned and if it's installed back-to-front or not. Once you know a thing, it's hard to un-see, or unlearn the background of it. <p> The same happens when I spot an antenna in the wild, stuck to a lamppost, or bolted to a random roadside cabinet. Previously they would go unremarked, today I wonder what information they're transmitting or receiving, what band they're operating on, who owns the equipment and what interference they might be causing or experiencing in their environment. <p> I have a growing interest in computer controlled manufacturing like 3D printing, laser engraving and CNC and spend some of the available time in the day learning about how that works, how to improve things and I wonder about how the speed of communications between the various components create an RF field of some sort and what that does to other components and circuits. <p> As a final experience, recently I had a medical procedure where there was a notice supplied with the logging hardware that specifically called out amateur radio as a source of electromagnetic radiation and that I was required to refrain during the process due to a potential failure of the equipment. If anything, for the first time in a long time, I felt that there was a visible link between my hobby and the rest of the community, since that notice was given to every single person, not just the radio amateurs. <p> Some links between amateur radio and the rest of the world are visible and some are not. What kinds of interactions between the hobby and society at large have you come across? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The diversity of our hobby is breathtaking.
Foundations of Amateur Radio <p> You've heard me say that amateur radio is a thousand hobbies in one. It's not my idea, but it speaks to me in ways that are hard to articulate. Today I found a way that might give you an inkling just how vast this community is. <p> One place where our community gathers is on-air, but it's not the only place. There are clubs, websites, email lists, video channels and other outlets all catering for different amateur radio users and their interests. One such place is the social media site Reddit. In the so-called amateurradio sub with currently over 88 thousand members, there is a lively community discussing many of the different aspects of our hobby. <p> Over the past 24 hours, 23 posts were made in that single community. <p> "Thanks, K-2722 hunters", was a photo about activating Carolina Beach State Park, as part of an activity called Parks on the Air, or POTA. To participate you can either go to a park, set-up your station and make contacts, or you can stay at home and listen out for people who are doing that. <p> "It's not high-high, it's hee-hee", a meme around the sound that the Morse Code generates when you send the letter H followed by the letter I, commonly considered laughter. <p> "Why don't scanners have FM radio?", a discussion around the perceived lack of FM mode on scanners. <p> "Help with TYT MD-380 CPS", a question from an amateur who purchased a new radio and is looking for software to program it. <p> "Portable on the Space Coast. QRP on a speaker wire antenna.", a video of an amateur making an activation in Florida and showing off their set-up. <p> "Could not hit DMR repeater", an amateur sharing that they figured out that they couldn't hit a repeater because they had their radio set to low power and wanted to share that with the community. <p> "Antenna advice part 2", asking about how to set-up antennas for dual use, how to amplify the signal, use rotators and what kind of coax to use. <p> "ISS SSTV Aug 6-7 145.800 MHz FM", linking to a news item announcing slow scan television coming from the International Space station in August. <p> "FT-3DR APRS message question", exploring the specifics on how Automatic Packet Reporting System or APRS messages are sent. Think of it as global distributed SMS via amateur radio. <p> "Is it okay to leave a handheld radio on while it's on its battery charger 24/7?", with answers to the question that's puzzling one owner of a radio. <p> "Extra test question", asking about how to learn for the test and wondering if the techniques needed are different when compared with obtaining the "tech" exam. <p> "Just got my first radio! Now to prep for the test, but first a question about saving time after I pass it...", asking about how to register before the test to speed things along. <p> And that's just over half way there. <p> "Maldol TMH-21 / TMH-71 handhelds - any info?", asking about a new to them radio from around 2007. <p> "2021 Berryville, VA (US) Hamfest - any reddit community members going?", looking for others going to the first hamfest in their region for a long time. <p> "CB Radio is Going FM! Why is the FCC Doing It?", linking to a video that discusses the changes on how CB radio is getting another mode. <p> "What is the 'right' way to learn morse?", the age-old question, one that I'm still am working through. <p> "Sidetone distorted on QCX mini? How do I fix this? It gets better or worse when I move the radio around, but the problem doesn't go away. Anyone else's QCX do this?", with a video showing the issue. <p> "Aluminium roof trim + HF dipole", with a question on what kind of effects might happen as a result of the combination of the two. <p> "Never owned a Radio be for please help lol. I got 2 of these on the way any tips for beginners? [sic]", excited new owner looking for advice. <p> "I finally got my qsl cards printed!", with pictures to show the artistic prowess involved. <p> "Legality of transmitting digital data over FM audio", asking about the specifics on how data may or may not be transmitted in the United States. <p> "It's no pie plate on a kayak, but you gotta work with what you have, right?", showing off a frying pan as a magnetic base. If it works, it's not silly at all. <p> "Very New Here", asking about how to explore radio waves. <p> Those 23 different posts are all about amateur radio, from one single community, on one day. Each post from someone finding their way in the community, discussing something that's important to them, sharing their experience and contributing to that community. Reddit alone has at least a dozen amateur related communities, covering electronics, specific radios, amateur software development and more. <p> The thing about this hobby is that it's different things to different people. For some it's about getting on air and making noise, for others it's learning about whatever comes their way. This hobby is so vast because it touches so many aspects of life, it innovates, leads and contributes in ways that are often invisible and that's why it's so engrossing. <p> What's your latest interest in this hobby and what keeps you coming back for more? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How are contests scored?
Foundations of Amateur Radio <p> The essential purpose of an amateur radio contest is to get on air and make noise. Each contest has a set of rules on how they intend to achieve this. An integral part of the rules is the idea that you establish a contact, a QSO, with another station and exchange some predefined information. Likely the callsign, a signal report and often something else, a serial number, the age of the operator, a maidenhead locator or the CQ or ITU zone. I'll race past the discussion around sending 5 and 9 as a standard signal report and move right along. <p> To validate your activity, you record this information in a log and after the contest has concluded, you share your log with the contest organiser who collates and processes the submitted logs to determine a winner. As a participant you look for your callsign on the results page and if you're lucky you get some form of trophy, a certificate, a plaque, or more often than not, a PDF. An amateur radio contest is not a particularly high stakes competition. <p> Recently I asked a group of contesters a question: "How do you learn why a QSO was excluded from your score?" I asked because one of the eight contacts I managed during a recent contest was disallowed, leaving me with an unexplained discrepancy between my log and the results. I will note that this entry didn't affect my ranking, I won my category, mainly because I was the only entrant - hah! <p> Depending on whom you ask, this is either a simple or a complex question. <p> The simple explanation states that if the contact isn't in the log of both stations it's not a valid contact. This interpretation was extremely popular in the group I asked. <p> It was not the only answer I received. <p> When I spoke with individual contesters they came up with different answers to my original question. <p> For example, if I log everything right, if I'm using a serial number, the number increments each time and my log shows that, then my log entry should be valid, even if the other station didn't log it correctly. Note that I said log, not copy, as-in, they repeated back what I gave them, but logged it incorrectly. <p> I also wondered what would happen if I was using a club-station callsign and accidentally called CQ with my own callsign and a station logged that callsign instead of the club-station. Should they be penalised because they logged what was actually exchanged? <p> There's more. <p> For example, what happens if the times are not identical? Based on the simple explanation, this would not be a valid contact, so you would not get recognition for this exchange and in some contests an invalid contact will produce a penalty to both stations. <p> Another variation to the simple answer occurs if the contest organiser doesn't receive a log for every station and as a result, some contests set a maximum number of contacts for stations without logs. <p> All this came within the context of attempting to discover how log validation happens, who decides what's valid and what rules are used. During my group conversation, two contest managers shared how they scored their particular contests and showed that they attempted to award the benefit of doubt to each station. One decided after the discussion to change their interpretation to the simple explanation I've already looked at. <p> I wanted to know if there was any standard and other than pointing vaguely in the direction of a few large contests, I didn't actually manage to find any definitive discussion on how this works, if it's universal, which I suspect it isn't, and if it changes over time, which I know it does. <p> The largest annual contest is the CQ World-Wide. In a 2012 blog post the contest committee discusses the time window of a contact and explains that they allow a 15 minute window, so as long as both contacts agree within 15 minutes, the QSO is allowed. That post also pointed out that if the time for one station was out by 45 minutes, none of their contacts would be allowed and anyone who made contact with that station would by implication get a penalty. <p> Clearly there are variations on how this is handled. <p> I asked if there is validation software for logs that checks this and if that software is open source so others can look at how decisions are made and see how these evolve over time. Is there an arbitration that goes beyond the standard phrasing in most contests: "The decision of the contest committee is final." <p> I was told that this wasn't necessary and I should focus on more practice. I beg to differ. I've been contesting for a decade now, I have plenty of winning certificates on my wall. I'd like to improve my skill and I'd like to learn why and how my contacts are disallowed and I'd like others to be able to do the same. <p> Log checking software is written by humans who interpret the rules and write software to conform to those rules. In order to see what rules are in place and to validate that, the source of that software must in my opinion be open and transparent. <p> As a community we sit at the boundary between professional communications and a hobby and we often use the idea and concepts of a contest to argue that this is the best way to hone skills and to make you a better operator in case of an emergency, but if you cannot actually learn from your mistakes, if there is no discussion on how decisions are made, if there's nothing beyond simple answers, then are we really striving for improvement or just set in our ways? <p> For the record, I think that if a contest log is off by 45 minutes throughout the entire log, software should pick that up, award the contacts and point out the mistake to the person who didn't set their clock correctly, especially since time is not exchanged during any contest I know. I also think that if a station logged what was actually said, there is room for that to be considered a valid exchange, but then I've only been an amateur contester for a decade, so I have plenty to learn. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Share if you care...
Foundations of Amateur Radio <p> When you explore the landscape of amateur radio you'll discover an endless array of innovation. There's websites with photos and descriptions of activities, places discovered and lessons learnt. If you watch the growing collection of YouTube channels you'll discover videos describing what people have been up to, commenting on videos they've seen and you'll start to notice that people all over the community are pinging off each other. Social media does the same. <p> If you read an amateur magazine, or a book, you'll unearth references and counter-references, links and credits, descriptions gleaned and tests made, all of them interlinking and adding to the knowledge base that underpins the amateur radio community and society beyond it. <p> The same is true for on-air activity. Look at contesting for example, you'll hear descriptions from other contesters, sharing their lessons learnt which potentially influence how you do your next contesting activity. The same is true for working DX, operating any digital mode, running an on-air net, running a SOTA activation, anything. <p> The point being that you are influenced by others and everything you do influences somebody somewhere else who in turn influences the next person who might then influence you. On and on the chain grows. <p> This chain of knowledge goes back to the early science in our hobby, the works of James Clerk Maxwell who for the first time brought electricity, magnetism, and light together as different manifestations of the same phenomenon in 1864. <p> The reason we know this is because he published his work and without needing to leave home to see the original, anyone can read it today from the comfort of their living room thanks to the PDF that's on the Royal Society web-site. <p> The point being that Maxwell documented his work and shared it with the world. <p> In our hobby we've gone through the process of making our equipment from unobtainium, requiring that the actual components were constructed before you could actually put them together and use them for their intended purpose. We then went on the scrounge for parts from other equipment, acquiring surplus gear and through a phase where you could buy new components off the shelf and attach them to an etched circuit board. That evolved into being able to design a board, ordering it online, having it built for cents and shipped to our door. <p> Today an increasing component of our hobby evolves around software with its unique property of transience. <p> Unlike physical components, software is intangible. You imagine how something might work, you describe it in an imaginary language, convert it into something that can be run inside a computer, and if you did it right, the outcome gives you the basis for your next experiment. <p> When software reaches a certain level of complexity it becomes impossible to remember. You tweak something over here and something over there changes and unless you can keep all that together inside your brain as a cohesive imaginary model, you quickly run into a brick wall. <p> If you're a software developer you've likely heard of tools like CVS, SVN and git. They are examples of revision control. They're used extensively in software development, but increasingly they're being used to track changes in documents, legislation and places where change is constant. <p> As an aside, if you load the various versions of legal requirements of your license into revision control, you'll quickly discover that your license is slowly evolving over time, for better or worse. From personal experience, I know doing that for the Radiocommunications Licence Conditions in Australia was very interesting indeed. <p> Each of these tools gives you the ability to tweak something, track it and if it doesn't work out, revert to where you started your experiment. It's a little like using a soldering iron and a soldering wick, physical undo for experiments. <p> When I talk about Open Source software, I'm not only talking about the ability to look inside and add functionality, I'm also talking about accessing the history that goes with that. <p> Open Source software generally only works if it comes with a revision history, a trail of discovery outlined right there on your screen showing what worked, why and how it came about. There's often options for showing who made what change, which changes happened at the same time and the ability to extract that particular change. All essential ingredients for experimentation. <p> Closed Source software does all those things, but privately. It too likely uses revision control tools, even the same ones as Open Source, but the discoveries are held in-house, behind closed doors, used by a select few. The software evolves inside the organisation, but there's no insight for or from the outside world. <p> Of course, everyone is entitled to keep their stuff secret, but if you want to make a contribution to society outside the life of your walled garden, the only way forward is to publish and share your work like scientists have been doing well before the Royal Society held its first meeting on the 28th of November 1660. <p> Share if you care... <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What Open Source means to our hobby and why it's important.
Foundations of Amateur Radio <p> For much of the past month I've been attempting to articulate what Open Source Software is, why it's important, how it's relevant to our hobby, how it works, how software is different from hardware and why you should consider if the equipment you buy comes with source code or not. I'm finding it difficult to separate out the issues since they all hang together in a cohesive clump of ideas and concepts. <p> So, let me go sideways to set the scene. <p> There is a movement that asserts the right to repair our own things and to ensure that manuals and diagnostic tools used by manufacturers are made available to the public. <p> For many radio amateurs that might sound quaint and obvious, since for much of the hobby that kind of information was not only available, it was expected and assumed to be available. You can get the circuit diagram and testing procedures, the alignment process and the list of required test equipment for most if not all amateur transceivers today and truth be told, if that testing gear isn't available, we tend to build or scrounge our own. <p> Compare a Yaesu FT-857d and an Icom IC-7300. They're radios from different generations, use different technologies, are made by different manufacturers and come in different packaging. <p> Both radios have user manuals, circuit diagrams and documented testing and alignment processes, but they're not equivalent even if they look the same. <p> The 857 is constructed from discrete components and circuits. There's a microprocessor on-board, the source code is not available and updates are issued by the manufacturer if and when it sees fit. Its function is to control and sequence things, selecting band filters, switching modes, updating the display and control serial communications. While integral to the functioning of the radio, the microprocessor itself is used for command and control only. <p> Inside the 7300 you'll also find discrete components. There are circuits, filters and the like and while individual components have reduced in size there are many of the same kinds of functions inside the radio as you'll find on an 857. The microprocessor inside the 7300 is more advanced than the one inside the 857. The source code is also not available and updates are issued by the manufacturer when it sees fit. <p> If that was all there was to it, I would not have spent a month attempting to capture this. Suffice to say that looks are deceiving. <p> The microprocessor inside the 7300 does the exact same things as the 857 with one minor difference. It now also forms part of the signal input and output chain of the radio itself. <p> Let me say that again. <p> The computer that is the heart of a modern radio is an integral part of the signal processing of the radio. Where in a traditional radio the microprocessor was switching circuits on and off to process the signal, the modern solution is to do all the signal processing using software inside the microprocessor itself. If you want to get technical, an FPGA is doing much of the signal processing, but that too is driven by software. <p> Where previously you had access to the circuit diagram that would show you what was being done to the signal, today you have a magic black box that does stuff completely outside your control. <p> If you want to know how an SSB or FM signal is decoded on the 857, the service manual will helpfully point you at two chips which provide those specific functions. It describes how the signal comes into the chip and how the signal is processed once it leaves the chip and if you need more, you can look online to find the specifications for each chip to see precisely what they do and how they work, complete with equivalent circuits and specifications. <p> On the other hand if you wanted to know the same information for the 7300 you'd be out of luck because if you dig deep enough, following the signal path, eventually you'd end up inside the microprocessor where software is making that happen. There's no description on how this works, what the circuit equivalent characteristics are, there's no way to change how it works, no way to set parameters, no way to see inside and no way to experiment. <p> This is a problem because it means that you've got a solution that's no longer operating in the spirit of amateur radio. It's not open for experimentation, it's not subject to review, there's no way to test, no means to improve, no way to do anything other than what the manufacturer decided was appropriate. <p> For example, if I wanted to modify the FM pass-band width on an 857, I could update the FM demodulation circuit by replacing a couple of components. On a 7300, I could not because there is no circuit. The FM demodulator is described in software that I don't have access to and Icom has decided that the FM pass-band is fixed. <p> If the software was open however, I could add this function and make it available to anyone who would like to experiment. <p> At this point I'd also like to observe that the Icom user manual states that inside the IC-7300 it uses open source "CMSIS-RTOS RTX", "zlib" and "libpng" software, so Icom is benefiting from open source efforts, but not sharing their own. <p> This is not an Icom only problem, this is a specific issue around open source versus closed source and while you might think that the right to repair and open source is something that's not relevant to you, I'd like to invite you to consider what the implications are for our hobby. Are we going to go down the road of button pushers, or are we continuing our role as inventors and experimenters? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What mode is that?
Foundations of Amateur Radio <p> The hobby of amateur radio is about communication. When you go on-air and make noise, you initiate a communications channel, sending information out into the world and hoping for another station to receive and decode what you sent. The channel itself can be used in an infinite number of ways and each one is called a modulation mode, or mode for short. The popular ones come with most radios, CW, AM, SSB and FM. <p> Those few are not the only ones available. In fact as computers are being integrated into the radio at an increasing pace, signal processing is becoming part and parcel of the definition of a mode and new modes are being introduced at break neck speed. I've talked about WSPR as an example of one such mode, but there are many, each with their own particular take on how to get information between two stations. <p> As you listen on the bands you'll increasingly find yourself hearing a bewildering litany of beeps, pops and clicks. Some of those are due to ionospheric conditions, but many are different modes that are being experimented with across our spectrum. <p> If you have access to a band scope, a way of visualising radio spectrum, you can actually see the shapes and patterns of such signals over time and getting to that point can be as easy as feeding your radio audio into your computer and launching a copy of fldigi or WSJT-X. <p> Every mode requires a specific tool to decode it and with practice you'll discover that there is often a particular look or sound associated with a mode. Over time you'll confidently select the correct decoder, using your brain for the process of signal identification. <p> Of course if you don't have access to the library in your brain yet, since you've only just started, or if the mode you've come across is new, you'll need another library to discover what you found. There is such a library, the Signal Identification Wiki. It's a web-site that hosts a list of submitted signals, grouped by usage type, including one for our community. <p> On the amateur radio page of the Signal Identification Wiki there are over 70 different modes listed, complete with a description, an audio file and a spectrogram. With that you can begin to match what you've discovered on your radio to what the web-site has in the library and determine if you can decode the incoming information. <p> I will mention at this point that the Signal Identification Wiki is far from complete. For example, the Olivia mode has 40 so-called sub-modes of which about 8 are in common use. Each of those sub-modes looks and sounds different. The wiki shows only a single line for Olivia. <p> I'm pointing this out because the wiki allows you to submit a mode for others to use. If you have a signal, either by recording it off-air, or better still, recording it directly from the source, consider submitting it to the wiki so others can benefit from your experience. <p> If you've come across a signal and you cannot figure out what it is, there are other places you can go for help. The four and a half thousand members of the /r/signalidentification sub on reddit will happily look at and listen to your signal and try to help. Make sure you contribute some meta data like the time, frequency and location to accompany the spectrogram and audio. <p> You might have come to this point wondering why I'm encouraging you to use and contribute to the wiki and ask for help on reddit. Amateur radio is about experimentation. We love to do that and as we make signal processing easier and easier, more people are making new modes to play with. <p> The speed at which this is happening is increasing and as an operator you can expect to come across new signals. I remember not that long ago, it was last month, tuning to an FT8 frequency and the person I was with asking what that sound was. They'd heard it before but never discovered its purpose, even though FT8 has been with us since the 29th of June 2017. <p> What interesting signals have you come across and how did you go with decoding them? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

When you share the hobby grows ...
Foundations of Amateur Radio <p> Recently I received a lovely email from Simon G0EIY, who reminded me that there is a voice-keyer that fits into a microphone. It was designed by Olli DH8BQA as a replacement for a standard Yaesu MH-31 microphone. I'd come across this a while ago and for several reasons put off actually ordering one, but Simon's encouragement tipped me over the fence and I've placed my order. <p> What I'm expecting to arrive at some point is a kit that has the minuscule surface mount components already soldered to a circuit board, leaving a couple of individual components ready for my soldering iron abuse. I'll let you know how it goes. <p> This little experience reminded me that I've been stumbling across solutions like this for years, an amateur with an itch to scratch and the drive to do something about it. <p> For example, Paul KE0PBR likes to operate satellites and in doing so amassed a collection of frequencies. Since the Doppler effect alters the actual frequency depending on the satellite coming towards you or moving away from you, there are corrections that need to be done. If you're in the field, this is something that you might struggle with, so Paul created a Frequency Cheat Sheet. <p> If you're looking into magnetic loop antennas, you'll quickly encounter a spreadsheet made by Steve AA5TB that will get you started with the parameters for designing and building your own magnetic loop. <p> The popular VK Contest Logger, known colloquially as VKCL was built by Mike VK3AVV. It's a simple to use logging tool that has a large collection of rules for different contests and Mike often brings out a new version to incorporate the latest rule changes just before a contest. It even incorporates a station log. <p> If you've come across apps like DroidPSK, DroidSSTV and DroidRTTY, they're the brain children of Wolfgang W8DA. The increasingly popular Repeaterbook maintained by a global community of volunteers is the work of Garrett KD6KPC. <p> I've lost count of the number of radio amateurs running an online shop where you can buy gear, or kits, or circuit boards, components, antennas, software and the like, not to mention an astonishing collection of professionally built tools like antenna analysers, filters, amplifiers and more. <p> It's said that amateurs are notorious for their short arms and deep pockets. I like to think of it as a discerning and informed customer. It's easy to sell snake-oil to the masses, it's been going on for centuries, it's much harder to do that when the person you're selling to knows how the thing you're selling works and knows how to read a data-sheet, let alone ask awkward questions when the need arises. <p> Before I go on I will mention that the people I've named here are unaware of me doing so. I've not been approached by any of them to mention their name and I have no relationship, other than being a happy customer. I'm saying this out loud because this podcast goes out on amateur radio repeaters all over the world and commercial use of amateur radio is strictly prohibited. <p> You might have gotten to this point wondering why I'm even taking the time to highlight some of the efforts I've come across and the reason is very simple. This activity is everywhere, you just have to look. It's not like Olli, Paul, Steve, Mike, Garrett or Wolfgang shouted their involvement from the rooftops, it's just that the information is available if you care to look. Remember, these people are radio amateurs just like you and I. <p> That's important because the difference between a tool that you're using that you built, sitting in your shack or on your computer and that of the people I've named is that they took an extra step and shared their efforts with the community. Some amateurs are making a living from this hobby and I applaud their efforts, for the rest of us, me included, that's often not the point. <p> Invention is happening all over the world, right now. You are doing it, despite your protestations to the contrary. You might have made a PDF that you carry around during a contest, or it might be a calculator you knocked up to figure out how to build something. It might be a circuit diagram, an app, a how to guide, a map or a video. All of these things are creations that can be shared to increase the amount of innovation that happens by people bouncing ideas off other ideas. <p> In 1675, Sir Isaac Newton said: "If I have seen further it is by standing on the shoulders of Giants." <p> You are one of those giants and the person who uses your contribution to make their own is standing on your shoulders. <p> What are you waiting for? <p> Publish, share, document, photograph and make available, it's how society makes progress and it's how amateur radio stays at the forefront of innovation. <p> Get on air and make noise is not purely restricted to the RF spectrum. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Here be Dragons, venturing into uncharted territory ...
Foundations of Amateur Radio <p> Sometimes when you head into uncharted territory, you gotta laugh at yourself from time to time. Last weekend I participated in a contest, something I enjoy doing as you might recall. To simplify the process of setting up in a vehicle I'd proposed a bold plan to save space and reduce complexity. I was anxious about reducing the amount of technology because I'd come up with a plan to use a paper log to track my contest contacts. <p> I had visions of operating for the best part of 24 hours and making hundreds of contacts. This was based on the fact that in 2016 I'd done this same contest on my own and made a 138 contacts and scored 18221 points, having moved 17 times. <p> I'd also done the contest in 2018 and for reasons I don't recall, I made one contact over 8 hours. <p> That right there should have been a warning sign that I might not quite get the result I'd been fearful of. <p> Blissfully unaware of the adventure that was unfolding, after driving to the first location, I called CQ for the better part of an hour. Then I called some more. When I was done with that, I called CQ more. 90 minutes in, I made my first contact. <p> That pretty much set the pattern for the next nine hours. At one point we feared that the radio had packed up, but then I made a 2900 km contact with the other side of the country between me in Perth in VK6 and Catherine VK7GH in Tasmania. <p> Around five pm we packed up, having moved location six times, making eight contacts and claiming 64 points, having worked three of the six states I heard. <p> Talk about overblown fears. <p> Looking back, even documenting 138 contacts on paper doesn't seem nearly as daunting after the fact, but that's for another day. I did learn some other things too. <p> I was worried about logging the band correctly, since using a computer that's not connected to the radio requires an extra step when you change band. Using paper the issue wasn't the band, it was remembering to record the time. <p> We didn't have the opportunity to test all the gear before the contest. I was bringing in some extra audio splitters, which didn't work with the set-up we had, testing before hand would have revealed that. We knew that there was a risk associated with not testing before and decided that in the scheme of things it didn't matter and we were right. It didn't. <p> We hadn't much planned for food and pit-stops, but having a GPS and an internet connection solved all those issues almost invisibly. Of course that wouldn't work in an unpopulated area, but we were well inside the metropolitan area of a big city, well, Perth. <p> Using a head-set worked great, though it didn't have a monitoring feature, so my voice got louder and louder and Thomas VK6VCR who took on the tasks of navigating and driving became deafer and deafer as the day progressed. <p> I keep coming back to wanting a portable voice-keyer, a device that you can record your CQ call into and then at the press of a button, play it back so you don't lose your voice whilst calling CQ hour after hour. The challenge seems to be that you need to find a way to incorporate it into the existing audio chain so it doesn't introduce interference. <p> Winning a contest requires contacts and that can only happen if there are other participants. This time around there didn't seem to be that many on air making noise. I think I heard a grand total of 13 stations. Some of that was due to propagation conditions which were nothing like I've ever heard before, but perhaps if I stick around for another solar cycle, that too will become familiar. Atrocious is one word that comes to mind. <p> Continuing our learning, the weather, not just space-weather, actual earth weather, snow, rain, hail and in our case sun. Neither of us thought to bring a hat since the forecast was for intermittent rain. We had no rain, instead had the opportunity to bask in the winter sun. Yes, it's winter here in Oz when it's Summer in Europe. As it happens, our winter temperatures are like your summer ones, but I'll leave it to you to confirm that for yourself. <p> Finally, we have a local phenomenon in VK6. When the sun goes down, the 40m band comes alive with the sounds of Indonesia. Among the radio amateurs are plenty of pirate stations with massive AM transmitters enjoying the conditions, chatting, chanting and what ever else comes to voice. Not conductive to being on-air and making noise, but as far as I can tell, not commonly heard outside of VK6. <p> That said, the Indonesian radio amateur community must have the patience of saints putting up with the interference that their non-licensed countrymen cause on a daily basis. My hat off to you! <p> As I've said all along, this radio thing is about getting on air and having fun and I can tell you, we did. <p> What did you get up to? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Removing technology for a change
Foundations of Amateur Radio <p> My first ever interaction with amateur radio was a field day on Boterhuiseiland near Leiden in the Netherlands when I was about twelve. The station was set-up in an army tent and the setting was Jamboree On The Air, or JOTA. My second field-day, a decade ago, was a visit to a local club set-up in the bush. At that point I already had my licence and I'd just started taking the first baby steps in what so-far has been a decade long journey of discovery into this amazing hobby. <p> A field day is really an excuse to build a portable station away from the shack and call CQ. A decade on, I vividly remember one member, Marty, now VK6RC, calling CQ DX and getting responses back from all over the world. <p> From that day on I looked for any opportunity to get on air and make noise. Often that's something I do in the form of a contest. I love this as a way of making contacts because each interaction is short and sweet, there's lots of stations playing from all over the planet and each contest has rules and scores. As a result you can compare your activity with others and look back at your previous efforts to see if you improved or not. <p> As you've heard me repeatedly say, I like to learn from each activity and see if there are things I could have done differently. I tend to think of this as a cycle of continuous improvement. <p> A few months ago a friend asked me if I was interested in doing a contest with him. For me that was a simple question to answer, YES, of course! <p> Over the last few months we've been talking about how we'd like to do this and what we'd like to accomplish. For example, for me there's been a regular dissatisfaction that during portable logging I've made mistakes with recording the band correctly in the log and having to manually go back and fix this, taking away from making contacts and having fun. To prevent that, I wanted to make sure that we had electronic logging that was linked to the radio in the same way as I do in my shack, so it didn't happen again. It was a small improvement, but I felt it was important. <p> Doing this meant that we'd either need to sort out a computer link, known as CAT, or Computer Assisted Tuning for his radio in the vehicle, or bring my radio, CAT control, power adaptors as well as bring a laptop, power supply and last but not least find space in the vehicle to mount all this so it would work ergonomically for a 24 hour mobile contest. The vehicle in question is the pride and joy of Thomas VK6VCR, a twenty-odd year old Toyota Land Cruiser Ute with two seats, three if you count the middle of the bench, and neither of us would ever be described as petite, so space is strictly limited. <p> In playing this out and trying to determine what needed to go where, we discovered that this wasn't going to work and I made the bold proposal to go old school and use a paper log. <p> This would mean that we could use the existing radio, without needing to sort out CAT control, the need for any power adaptors, no space required for a laptop, no power for that, no extra wiring in the vehicle, and a whole lot more simplicity. So that's what we're doing, paper log and a headlamp to be able to see in the dark. <p> I must confess that I'm apprehensive of this whole caper, but I keep reminding myself that this too is an experience, good or bad, and at the end of the day, we're here to have fun. I might learn that this was the worst idea I've ever had, or I might learn that this works great. It's not the first time I've used a paper-log, so I'm aware of plenty of pitfalls, not the least of which is deciphering my own handwriting, the ingenuous project of three, or was it four, different handwriting systems taught to me by subsequent teachers in different countries. There's the logistics of being able to read and write at an odd distance, trying to work out how to operate the microphone with the wrong hand, though we are trialling a headset and boom microphone with a push to talk button, and then there's the radio, one I've used before, but not in a contest setting and not whilst driving around on the seat of a 4WD hell-bent on rattling my teeth from their sockets. <p> On the plus side, I've done a contest with my friend before and he is familiar with my competitive streak and we're both up for a laugh, so I'm confident that despite the challenges that lie ahead, we're going to make fun and enjoy the adventure. <p> I can't wait to find out if simplifying things will result in a better experience and only trying it will tell. I'll let you know how it goes. <p> When was the last time you stepped out of your comfort zone and what did you do? How did it work out? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What radio should I buy as my first one?
Foundations of Amateur Radio <p> Recently a budding new amateur asked the question: "What radio should I buy?" <p> It's a common question, one I asked a decade ago. Over the years I've made several attempts at answering this innocent introduction into our community and as I've said before, the answer is simple but unhelpful. <p> "It depends." <p> Rather than explaining the various things it depends on, I'm going to attempt a different approach and in no particular order ask you some things to consider and answer for yourself in your journey towards an answer that is tailored specifically to your situation. <p> <p> "What's your budget?" <p> How much money you have set aside for this experiment is a great start. In addition to training and license costs, you'll need to consider things like shipping, import duties and insurance, power leads and a power supply, coax leads and connectors and last but not least, adaptors, antennas and accessories. <p> <p> "Should you buy second hand or pre-loved?" <p> If you have electronics experience that you can use to fix a problem with your new to you toy this is absolutely an option. When you're looking around, check the provenance associated with the equipment and avoid something randomly offered online with sketchy photos and limited information. Equipment is expensive. Check for stolen gear and unscrupulous sellers. <p> <p> "What do you want to do?" <p> This hobby is vast. You can experiment with activities, locations, modes and propagation to name a few. If you're looking at a specific project, consider the needs for the accompanying equipment like a computer if what you want to explore requires that. You can look for the annual Amateur Radio Survey by Dustin N8RMA to read what others are doing. <p> <p> "What frequencies do you want to play on?" <p> If you have lots of outdoor space you'll have many options to build antennas from anything that radiates, but if you're subject to restrictions because of where you live, you'll need to take those into account. You can also operate portable, in a car or on a hill, so you have plenty of options to get away from needing a station at home. <p> <p> "Are there other amateurs around you?" <p> If you're within line of sight of other amateurs or a local repeater, then you should consider if you can start there. If that doesn't work, consider using HF or explore space communications. There are online tools to discover repeaters and local amateurs. <p> <p> "Is there a club you can connect to?" <p> Amateur radio clubs are scattered far and wide across the planet and it's likely that there's one not too far from you. That said, there are plenty of clubs that interact with their members remotely. Some even offer remote access to the club radio shack using the internet. <p> <p> "Have you looked for communities to connect with?" <p> There is plenty of amateur activity across the spectrum of social media, dedicated sites, discussion groups, email lists and chat groups. You can listen to podcasts, watch videos, read eBooks and if all that fails, your local library will have books about the fundamental aspects of our hobby. <p> <p> "Have you considered what you can do before spending money?" <p> Figuring out the answers to many of these questions requires that you are somewhat familiar with your own needs. You need a radio to become an amateur, but you need to be an amateur to choose a radio. To get started, you don't need a radio. If you already have a license you can use tools like Echolink with a computer or a mobile phone. If you don't yet have a license, you can listen to online services like WebSDR, KiwiSDR and plenty of others. You can start receiving using a cheap RTL-SDR dongle and some wire. <p> <p> "Which brand should you get?" <p> Rob NC0B has been testing radios for longer than I've been an amateur. His Sherwood testing table contains test results for 151 devices. The top three, Icom, Kenwood and Yaesu count for more than half of those results. This means that you'll likely find more information, more support and more local familiarity with those three. I will point out that Rob's list has 27 different brands on it, so look around and read reviews both by people who test the gear and those who use it. <p> <p> And finally, "Why are you here?" <p> It's a serious question. Different things draw different people into this community. Think about what you like about it and what you want to do more of. Take those things into consideration when you select your radio. <p> <p> As you explore the answers to these questions, you'll start building a picture of what amateur radio means to you and with that will come the answer to the question: "What radio should I buy as my first one?" <p> If there are other questions you'd like to ask, don't hesitate to get in touch. My address is cq@vk6flab.com. I look forward to hearing from you. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Bringing chaos into order
Foundations of Amateur Radio <p> One of the questions you're faced with when you start your amateur journey is around connectors. You quickly discover that every piece of equipment with an RF socket has a different one fit for purpose for that particular device. <p> That purpose includes the frequency range of the device, but also things like water ingress, number of mating cycles, power levels, size, cost and more. <p> As an aside, the number of mating cycles, how often you connect and disconnect something is determined by several factors, including the type of connection, manufacturing precision and the thickness of the plating. That said, even a so-called low cycle count connector, like say an SMA connector lasting 500 cycles will work just fine for the next 40 years if you only connect it once a month. <p> Back to variety. My PlutoSDR has SMA connectors on it as do my band pass filters, my handheld and one RTL-SDR dongle. The other dongle uses MCX. Both my antenna analyser and UHF antenna have an N-type connector which is the case for my Yaesu radio that also has an extra SO239 which is what my coax switches have. My HF antenna comes into the shack as an F-type and nothing I currently own has BNC, but stuff I've previously played with, does. <p> When you go out on a field-day, you mix and match your gear with that of your friends, introducing more connectors and combinations. <p> Invariably you acquire a collection of adaptors. At first this might be only a couple, quickly growing to a handful, but after a while you're likely to have dozens or more. My collection, a decade's worth, which currently includes more than 25 different combinations is over a hundred individual adaptors and growing. <p> For most of the time these have been tossed into a little tool box with a transparent lid, but more and more as the collection and variety grew I started to realise that I was unable to quickly locate an adaptor that I was sure I had, since it had been used in a different situation previously. <p> In addition to coming to the realisation that the reason I couldn't find a connector was because it was still in use, I began to notice that I had daisy chains of connectors. <p> For example, my HF antenna has a PL259 connector that is adapted to an F-type connector with an SO239 barrel, a PL259 to BNC and a BNC to F-type adaptor. At the other end of the RG6 coax that runs from outside into the shack, the reverse happens, F-type to BNC and BNC to PL259. If you're counting along, that's five adaptors to get from PL259 to PL259 via F-type. <p> At this point you might wonder why I'm using RG6 coax. The short answer is that I have several rolls of it, left over from my days as an installer for broadband satellite internet. RG6 is very low loss, robust and heavily shielded. Although it's 75 Ohm - a whole other discussion - in practice that's not an issue. What is a problem is that the only connectors available for it are F-type compression connectors. To get those to PL259 requires a step sideways via BNC. <p> My point is that the number of adaptors is increasing by the day. <p> I should acknowledge the existence of so-called universal connector kits. The idea being that you go from one connector to a universal joiner and from that to another connector. Generally these kits have around 30 connections, giving you plenty of options, but in reality more often than not, you only have half a dozen universal joiners, so your money is effectively buying you half a dozen conversions, great for a field day, not so great for a permanent installation. You could build your own collection and use something like SMA or BNC as your universal joiner, which is something I'm exploring. <p> To keep track of my collection, recently I started a spreadsheet. It's essentially a list showing the number and types of connections. If you make a pivot table from that you'll end up with a grid showing totals of adaptors you have. <p> You can use this grid to fill a set of fishing tackle boxes and all of a sudden you've got a system where everything has its own place. <p> If you start this process you'll quickly notice that the table only needs to be half filled, since a BNC to SMA is the same as an SMA to BNC adaptor. This leaves you space to do some fancy footwork where the bottom right hand of the triangle can fit into the top left of the empty space, but I'll leave you to figure that out. <p> My table also includes things like TNC and MCX adaptors, but I don't use those very often, so at the moment I'm putting them in their own box together with T-adaptors and other weird and wonderful things like FME and reverse SMA. <p> For setting the order, I've gone for alphabetic, but if you have a better suggestion, I'm all ears. My email address as always is cq@vk6flab.com. <p> What ideas have you come up with to organise the chaos that is your sprawling connector library? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Streaming a dozen repeaters with an RTL-SDR dongle
Foundations of Amateur Radio <p> A while ago as part of my ongoing exploration into all things radio I came across a utility called rtlsdr-airband. It's a tool that uses a cheap software defined radio dongle to listen to a station frequency or channel and send it to a variety of different outputs. Originally written by Tony Wong in 2014, it's since been updated and is now maintained by Tomasz Lemiech. There are contributions by a dozen other developers. <p> The original examples are based around listening to Air Traffic Control channels. I know of a local amateur who uses it to listen to and share the local emergency services communication channels, especially important during local bush fires. <p> While sophisticated, it's a pretty simple tool to use, runs on a Raspberry Pi, or in my case, inside a Docker container. It's well documented, has instructions on how to compile it and how to configure it. <p> Before I get into what I've done, as a test, let's have a look at the kinds of things that rtlsdr-airband can do. <p> First of all, it's intended to be used for AM, but if you read the fine documentation, you'll learn that you can also make it support Narrowband FM. It can generate output in a variety of different ways, from a normal audio file, to an I/Q file - more about that at another time, and it can also send audio as a stream to a service like icecast, broadcastify or even to your local pulse audio server. If that last one doesn't mean much to you, it's a local network audio service, popular under Linux, but it runs on pretty much anything else thanks to the community efforts of many. <p> So, on the face of it, you can listen to a channel, be it AM or Narrowband FM, and send that to some output, but I wouldn't spend anywhere as much time on this if that was all there was to it. <p> The software can also dynamically change channels, support multiple dongles, or simultaneously listen to several channels at once and output each of those where ever you desire. <p> Another interesting thing and ultimately the reason I thought to discuss it here is that rtlsdr-airband also supports the concept of a mixer. You can send multiple channels to a single mixer and output the result somewhere else. <p> Using a mixer, in addition to setting cut off frequencies and other audio attributes, you can set the audio balance for each individual channel. This means that you can mix a channel exclusively to the left ear, or to the right ear, to both, or somewhere in between. <p> Now, to add one extra little bit of information. <p> In my location there's about a dozen or so amateur repeaters most of which can be heard at some time or another from my QTH. The frequency spread of those dozen repeaters is less than 2 MHz. A cheap RTL-SDR dongle can handle about 2.56 MHz. <p> Perhaps you've not yet had the ah-ha moment, but what if you were to define an rtlsdr-airband receiver that listened to a dozen amateur radio repeaters - at the same time - and using the audio balance spread those repeaters between your left and right ear, you could stream that somewhere and listen to it. <p> I'm sitting here with my headphones on, listening to the various repeaters do their idents, various discussions on different repeaters, a local beacon, incoming AllStar and other links, all spread out across my audio horizon, almost as if you can see where they are on the escarpment, though truth be told, I've just spaced them out evenly, but you get the idea. <p> My original Raspberry Pi wasn't quite powerful enough to do this in the brute force way I've configured this, so as a proof of concept I'm running it on my main computer, but there's nothing to suggest that doing a little diligent tweaking won't make my Pi more than enough to make this happen. <p> As for audio bandwidth, it's a single audio stream, so a dial-up connection to the internet should be sufficient to get the audio out to the world. <p> I will point out that there may be legal implications with streaming your local amateur repeaters to the world, so don't do that without checking. <p> For my efforts, this is an example of: "I wonder if ..." <p> As it turns out, Yes you can. As it happens, my next challenge is to use this code on a PlutoSDR where the bandwidth is slightly larger, mind you, I'll have to do some fancy footwork to process the data without overwhelming the CPU, but that's another experiment in my future. <p> What kind of crazy stuff have you tried that worked? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Soldering Irons and Software
Foundations of Amateur Radio <p> The activity of amateur radio revolves around experimentation. For over a century the amateur community has designed, sourced, scrounged and built experiments. Big or small, working or not, each of these is an expression of creativity, problem solving and experimentation. <p> For most of the century that activity was accompanied by the heady smell of solder smoke. It still makes an appearance in many shacks and field stations today, even my own, coaxed by an unsteady hand, more and more light and bigger and bigger magnification, I manage to join bits of wire, attach components and attempt to keep my fingers from getting burnt and solder from landing on the floor. <p> I've been soldering since I was nine or so. I think it started with a Morse key, a battery and a bicycle light with a wire running between my bedroom and the bedroom of my next door neighbour. In the decades since I've slightly improved my skill, but I have to confess, soldering isn't really my thing. <p> My thing is computers. It was computers from the day I was introduced in 1983 and nothing much has changed. For reasons I don't yet grasp, I just get what computers are about. They're user friendly, just picky whom they make friends with. <p> When I joined the amateur community, it was to discover a hobby that was vast beyond my wildest imagination, technical beyond my understanding and it was not computing. Little did I know. <p> Computing in amateur radio isn't a new thing. For example, packet radio was being experimented with in 1978 by members of the Montreal Amateur Radio Club, after having been granted permission by the Canadian government. In 2010 when I came along we had logging, DX-clusters and the first weak signal modes were already almost a decade old. <p> Software Defined Radio has an even longer history. The first "digital receiver" came along in 1970 and the first software transceiver was implemented in 1988. The term "software defined radio" itself was 15 years old when I joined the hobby and truth be told, it's a fascinating tale, I'll take a look at that at another time. <p> When I started my amateur journey like every new licensee, I jumped in the deep end and kept swimming. From buying a radio, to discovering and building antennas, from going mobile to doing contests and putting together my home station, all of it done, one step at a time, one progressive experiment after another, significant to me, but hardly world shattering in the scheme of things. <p> Now that I've been here for a decade I've come to see that my current experiments, mostly software based, are in exactly the same spirit as the circuit builders and scroungers, except that I'm doing this by flipping bits, changing configurations, writing software and solving problems that bear no relation to selecting the correct combination of capacitance and reactance to insert into a circuit just so. <p> Instead I'm wrestling with compilers, designing virtual machines, sending packets, debugging serial ports and finding new and innovative ways to excite transceivers. <p> For example, today I spent most of the day attempting to discover why when I generate a WSPR signal in one program, it cannot be decoded by another. If that sounds familiar, that was what I was doing last week too. This time I went back to basics and found tools inside the source code of WSJT-X and started experimenting. I'm still digging. <p> As an aside I was asked recently why I want to do this with audio files and the short answer is: Little Steps. <p> I can play an audio file through my Yaesu FT-857d. I can receive that and decode it. That's where I want to start with my PlutoSDR experiments, so when I'm doing this, I can use the same audio file and know that the information can be decoded and that any failure to do so is related to how I'm transmitting it. <p> Back to soldering irons and software. In my experience as an amateur it's becoming increasingly clear that they're both the same thing, tools for experimentation, with or without burning your fingers. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Getting started on WSPR with a PlutoSDR
Foundations of Amateur Radio <p> As you might recall, I took delivery of a device called a PlutoSDR some time ago. If you're not familiar, it's a single-board computer that has the ability to transmit and receive between 70 MHz and 6 GHz. The system is intended as a learning platform, it's open source, you get access to the firmware, compilers and a whole load of other interesting tools. I used it to play with aviation receive using a tool called dump1090 which I updated to use Open Street Map. If you're interested, it's on my VK6FLAB github page. <p> Over the past few months I've been steadily acquiring little bits and pieces which today added up to a new project. <p> Can I use my PlutoSDR to transmit WSPR? <p> This all started because of an experiment and a conversation. <p> The experiment was: "Using my FT-857d on 70cm can I transmit a weak signal mode like WSPR and have my friend on the other side of the city decode the transmission?" The answer to that was a qualified "Yes". I say qualified, since we weren't able to transmit a WSPR message, but using FT8 we were happily getting decodes across the city. We're not yet sure what the cause of this difference is, other than the possibility that the combined frequency instability at both ends was large enough to cause an issue for a WSPR message, which lasts about two minutes. On the other hand, I learned that my radio can in fact go down to 2 Watts on 70cm. I've owned that radio for over a decade, never knew. <p> Now that I have a band pass filter, some SMA leads and the ability to talk to my Pluto across the Wi-Fi network, I can resurrect my Pluto adventures and start experimenting. <p> I mentioned that this was the result of an experiment and a conversation. <p> The conversation was about how to create a WSPR signal in the first place. At the moment if you run WSJT-X the software will generate audio that gets transmitted via a radio. All fine, except if you don't have a screen or a mouse. Interestingly a WSPR transmission doesn't contain any time information. It is an encoded signal, containing your callsign, a maidenhead locator - that's a four or six character code representing a grid square on Earth, and a power level. That message doesn't change every time your transmitter starts the cycle, so if you were to create say an audio file with that information in it, you could just play the audio to the nearest transmitter, like a handheld radio, or in my case a Pluto, and as long as you started it at the right time, the decoding station wouldn't know the difference. <p> As an aside, if you're playing along with your own Pluto, and far be it for me to tell you to go and get one, you can set the Pluto up using either USB, in which case it's tethered to your computer, or you can get yourself a USB to Ethernet adaptor and connect to it via your network. If you have a spare Wi-Fi client lying around, you can get that to connect to your Wi-Fi network, connect the Pluto via Ethernet to the Wi-Fi client and your gadget is connected wirelessly to your network. I can tell you that this works, I'm typing commands on the Pluto as we speak. <p> As is the case in any experiment in amateur radio, you start with one thing and work your way through. At the moment I want to make this as simple as possible. By that I mean, as few moving parts as I can get away with. I could right now fire up some or other SDR tool like say GNU Radio and get it to do the work and make the transmission, but what I'd really like to do is actually have the Pluto do all the work, so I'm starting small. <p> Step One is to create an audio file that I can transmit using the Pluto. <p> It turns out that Step One isn't quite as simple as I'd hoped. I located a tool that actually purports to generate an audio file, but the file that it builds cannot be decoded, so there's still some work to be done. <p> On the face of it the level of progress is low, but then this whole thing has been going for months. The experiment on 70cm lasted half an hour, the discussion took all of a cup of coffee. So far, I've spent more time on this project making the Wi-Fi client talk to my network than all the rest put together and that includes finding and ordering the Pluto in the first place. <p> You might well wonder why I'm even bothering to talk about this as yet unfinished project. The reason is simple. Every day is a new one. Experiments are what make this hobby what it is and every little thing you learn adds to the next thing you do. Some days you make lots of progress, other days you learn another way to not make a light bulb. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Ergonomics in your shack
Foundations of Amateur Radio <p> In my day job I work in computing. For many years that consisted of going on-site and fixing stuff. Invariably this involved me fixing servers that were installed into a room the size of a broom closet with an optional air conditioner screaming in my ear. The experience often included sitting on a crate, or the floor, holding a keyboard and if it was a Windows Server, rolling a mouse on my knee in order to click on stuff barely discernible on a tiny screen that likely sat a meter too high above my eye line with Ethernet wires going diagonally from one end of the room to the other. <p> These days with ubiquitous internet connectivity that kind of experience is mostly a thing of the past. <p> That said, operating a radio during a contest in many stations I've used over the years is not far from that kind of layout. <p> Often a traditional shack starts off with a radio on a table with a notepad to record contacts. Over time that gets expanded with technology like a computer. It's common to have to juggle the radio display and keyboard, to find a spot for the mouse that doesn't interfere with the desk microphone, or to have to reach over to change band and to activate a different filter, select another antenna, use the rotator or some other essential tool that's required for making that elusive contact. <p> Some stations have multiple monitors, sometimes they're even together, but more often than not they're a different size, sitting too high and the radio sits as a road-block between your eye line between the screen and the keyboard. <p> I'm raising this because over the years I've not actually seen anyone spend any energy on discussing how you might improve this experience. <p> If this was your workplace, the occupational health and safety police would be all over you and for good reason. You could argue that amateur radio is a hobby and that OH&S is of lesser concern, but to that I'd like to point out that you have the same risk of self injury at work as you do in your shack, especially if you're doing a contest for 24 or 48 hours. <p> Not only is there a risk of injury, why make the experience harder than it needs to be? Ergonomics is the process of designing or arranging a workplace to fit the user. It's a deliberate process. You have to actually stop to consider how you are using a space, in this case your shack. <p> At the moment I'm experimenting with different aspects of the layout of my shack. For example, I started with a layout of the computer, counter intuitive perhaps, since we're talking about a radio shack, but given that I'm spending much of my time doing contests and digital modes, the computer is used much more than the radio is, even if the radio is what's making all the on-air noise. <p> After making sure that my keyboard, mouse and screen were in locations that actually helped me, I started trying to figure out where to put the radio and what role it actually plays in making the contact. If during a contest you're using search and pounce, which is when you hunt up and down the bands looking for a contact, you might argue that you'll need access to the radio to change frequency, but if you already have your computer connected to the radio, you can change frequency from the keyboard or by control with your mouse. <p> Another way I'm looking on reducing the amount of stress to my body whilst operating my station is by sorting out audio. Almost every radio has a speaker on it, but if you've got more than one going at the same time it becomes really difficult to determine which one is actually making noise and even harder if multiple stations are on different frequencies on different radios at the same time. <p> You could wear headphones and select a radio, one at a time, either by plugging in a particular radio, or by using a selector. If you're using digital modes, the audio might already be going into the computer, which offers you the ability to select from different sound cards, but there are other options. I'm working on plugging the audio from each radio into an audio mixer that will allow me to set the level for each radio independently, mute at will, set the tone, the balance between left and right ear and a few other things. <p> For a microphone I plan on using the same mixer and I'm working on how to have my digital audio coming from the computer incorporated into the same audio environment, because the digital audio could just as easily be a voice caller using the same system. <p> For push to talk I settled on a foot switch a couple of years ago. That said, if I'm on my own, I tend to use VOX, or voice operated switching, which turns on the transmitter when microphone audio is detected by the radio. This will need some careful planning if I'm going to connect multiple radios, since I don't want to transmit the same message across each radio at the same time, but with computer control, that too can be addressed. <p> My point is that we have lots of technology available to us as radio amateurs to achieve what ever we need to. It takes extra effort to decide how you might go about making your environment a place where you can safely sit and operate without making life harder than it needs to be. <p> What kinds of different techniques and technologies have you used to make your shack a more comfortable environment? Do you spend your days hunting DX, doing contests or making digital contacts, or something else? Have you considered how you might improve the layout of your shack to suit your particular use-case and when was the last time you checked to see if the decisions you originally made are still valid today? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How much bandwidth is there?
Foundations of Amateur Radio <p> Have you ever taken a moment to consider the available bandwidth on the various amateur bands? <p> As an entrant into amateur radio in Australia as a Foundation licence holder you have access to six different amateur bands, the 80m band, 40m, 15m, 10m, 2m and 70cm. If you add the bandwidth from each of those bands together, you end up with 26.65 MHz worth of bandwidth to play with in Australia. <p> I can tell you that's a big chunk of bandwidth, but until I give you some context, 26.65 MHz isn't likely something that you can picture. <p> You might think of things as being pretty crowded. For example, on the 40m band during a contest it's common to hear wall to wall signals. There's barely enough room to call CQ and not interfere with anyone else. But how crowded is it really? <p> Let's start with an SSB signal, typically it's 2.4 kHz wide. On the 40m band, with 300 kHz of bandwidth, there's room for about 125 SSB signals side-by-side. On the 10m band, there's space for over 700 SSB signals side-by-side. Across all the available bandwidth for a Foundation license holder in Australia, there's room for over 11-thousand different SSB signals side-by-side. <p> While we're on the subject of crowding, there's talk about the massive influx of FT8, some call it a scourge. FT8 channels are transmitted within a single SSB channel and each takes up 50 Hz. That means that within an SSB channel of 2.4 kHz, there's room for 48 different FT8 channels, and if you take into account the odd and even time-slots, that doubles to 96 different signals, all within the same single SSB channel. So while FT8 is popular and growing, let's not get too excited about how much space it's taking up. From the perspective of an Australian Foundation license holder, it's taking up exactly six separate SSB slots of those 11-thousand across the six available bands, room for 576 separate FT8 signals, taking up a total of 14.4 kHz, or 0.05% of the available bandwidth. <p> Let's look at this another way, of the 26.65 MHz available bandwidth, 20 MHz is from the 70cm band alone, that means that all the other bands put together, fit inside the 70cm band three times over. <p> Let that sink in for a moment, adding the 80m, 40m, 15m, 10m and 2m band together fit inside the 70cm band three times. <p> You can use the 70cm band alone for 800-thousand FT8 signals, remember that there's two time slots, so you get two for one. <p> If this makes your mind explode, then consider that a carrier wave signal is considered to be about 25 Hz wide, so on the 70cm band you could have 800-thousand individual CW signals. You could allocate a personal CW frequency to every one of the amateurs in the United States in the 70cm band and still have room for expansion, not that I'm advocating that, just to give you a sense of scale. I should note that the 70cm band in the United States is even larger than it is in Australia, but I don't want to get bogged down into the various band plans across the world at the moment. <p> You might ask yourself why am I getting so excited about this? <p> Amateur radio is about experimentation. I've been telling you about HF propagation and using techniques like FT8 to determine just how far your signal goes, but you could use the same techniques to build a 70cm communication network with the amateurs within your city and share information across the city, perhaps even build a mesh network using your 70cm hand-held and an FT8-call network. It could be used to distribute propagation information, or messages in case of an emergency, or form the basis of something completely different. <p> If that doesn't whet your appetite, consider that the 1mm amateur band, which runs from 241 to 250 GHz is ready for you to experiment when your license permits. The current world distance record is 114 km, set in 2008 by Brian WA1ZMS and Peter W4WWQ, it has 9 GHz bandwidth and has room for 360-million FT8 signals, or 60 exclusive FT8 channels for every amateur on the planet. <p> My point is that as radio amateurs we have access to a massive chunk of radio bandwidth and it's just sitting there waiting for you to experiment with. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The massive physics phenomenon just over eight minutes away ...
Foundations of Amateur Radio <p> If you've been around radio amateurs for a little while you're likely to have heard about the Solar Cycle and that it affects radio propagation for HF or High Frequency, also known as shortwave communications. The frequencies in the range of around 3 to 30 MHz, or 100m to 10m wavelength. One of the main ways it's used is for is for long distance or global communication and one of the most common ways that's done is using the ionosphere around the globe to refract a radio signal. <p> In September 2020, the Solar Cycle 25 Prediction Panel, announced that Solar Cycle 25 had commenced in December 2019 and radio amateurs around the globe rejoiced. <p> The first question for me was, why Solar Cycle 25? <p> You might think of the Sun as a stable light in the sky. As it happens, the bright light hides all manner of ferocious activity. One of the measures of this activity is the number of dots observed on the surface of our Star. These dots are called sunspots. As Solar activity increases, the number of sunspots increases. The activity is cyclical, it increases and decreases over time. Each increase and decrease combined is known as a Solar Cycle. <p> On average a cycle lasts about 10.7 years. Simple maths gives you that Solar Cycles started somewhere around 1750. That seems a little strange. Our Sun is 4.6 billion years old. There are paintings on the rocks at Ubirr in the Northern Territory of Australia that are 40 thousand years old. The pyramids in Egypt are 45 hundred years old. The Solar Cycle has been going for a lot longer than the 7 million years there have been humans on the planet, let alone dinosaurs who experienced the Solar Cycle 66 million years ago. Using fossil records we've determined that the Solar Cycle has been stable for at least the last 700 million years. <p> Chinese astronomers recorded Solar activity around 800 BC and Chinese and Korean astronomers frequently observed sunspots but no known drawings exist of these observations. The first person to draw sunspots was John of Worcester on the 8th of December 1128. Five days later, half a world away in Korea on the 13th of December 1128, the astronomers in Songdo reported a red vapour that "soared and filled the sky", describing the aurora borealis in the night sky that resulted from those very same sunspots. <p> In the early 1600's there was plenty of activity around the recording of sunspots. Thomas Harriot appears to have predated Galileo Galilei by more than a year with notes and drawings dated the 8th of December 1610. There's plenty of other names during this period, Father and son David and Johannes Fabricius and Christoph Scheiner to name three, but I'm moving on. <p> The Solar Cycle, was first described by Christian Horrebow who more than a century later in 1775 wrote: "it appears that after the course of a certain number of years, the appearance of the Sun repeats itself with respect to the number and size of the spots". Recognition of the Solar Cycle was awarded to Samuel Heinrich Schwabe who noticed the regular variation in the number of sunspots and published his findings in a short article entitled "Solar Observations during 1843" in which he suggested that the cycle was 10 years. <p> Stay with me, we're getting close to Solar Cycle number One. <p> In 1848 Rudolf Wolf devised a way to quantify sunspot activity. His method, named the Wolf number, is still in use today, though we call it the relative or international sunspot number. In 1852 he published his findings on all the available data on sunspot activity going back to 1610 and calculated the average Solar Cycle duration as 11.11 years. He didn't have enough observations to reliably identify Solar Cycles before 1755, so the 1755-1766 Solar Cycle is what we now consider Solar Cycle number One lasting 11.3 years with a maximum of 144.1 sunspots in June of 1761. <p> Until 2009 it was thought that there had been 28 Solar Cycles between 1699 and 2008 with an average duration of 11.04 years, but it appears that the 15 year Solar Cycle between 1784 and 1799 was actually two cycles, making the average length only 10.7 years. I should also point out that there have been Solar Cycles as short as 8 years and as long as 14 years. <p> With the announcement of Solar Cycle 25 comes improved propagation for anyone who cares to get on air and make noise. The current predictions vary depending on the method used, ranging from a very weak to a moderate Solar Cycle 25. There are predictions for the Solar maximum, the time with the most sunspot activity, to occur between 2023 and 2026 with a sunspot range between 95 and 130. By comparison during the previous Solar Cycle, in 2011 the first peak hit 99 and the second peak in 2014 hit 101. <p> I have purposely stayed away from electromagnetic fields, geomagnetic impacts and the actual methods for HF propagation, I'll look at those another time. <p> I can tell you that we've gone a little beyond counting dots on the Sun to determine activity and we have a whole slew of satellites orbiting our Star doing all manner of scientific discovery, all of which helps our understanding of what's going on in the massive physics phenomenon 8 minutes and 20 seconds away by radio. <p> That said, Solar eruptions are still pretty unpredictable, much like the weather around us. Not because we don't want to know, but because this is a very complex one to solve, much like ionospheric propagation is hard to forecast, much easier to measure actual performance and much more accurate. <p> So, if you want to know how well propagation is going to be today, turn on your radio and have a listen. If you want to know how great it's going to be tomorrow, look at the forecast, but bring an umbrella, or an FT8 transmitter. <p> I'm Onno VK6FLAB.
Listen: podcast - audio/mp3

The dynamic nature of your shack
Foundations of Amateur Radio <p> If you have the opportunity to build your shack, it might start off as a table in the corner where you plonk down a radio, plug into nearby power and run coax to. That's pretty much how most shacks start, mine included. <p> For me the step of running coax was an activity that took weeks of planning and procrastination and days of climbing on the roof. After actually completing that and getting two runs of coax to my planned shack, one for HF and one for UHF and VHF, the shack building itself was pretty simple. <p> I had to get power to the location, but an extension lead took care of that. In the interest of space I put the power supply on the floor, a wooden floor that ensured good circulation, unlike carpet, perhaps a topic for another day, I plugged my coax into the radio, plugged in the 12 Volt power and was up and running. <p> Over time that space continued to grow. Looking at it right now, it has two computer monitors, a laptop, three radios, two coax switches, a keyboard, mouse, digital interface, two speakers, and a fan to cool the radio when I'm calling CQ on FT8. <p> I'm not a messy person, but I do like to have my tools convenient. It's not a pristine environment by any stretch, but it's orderly as shacks go. An hour ago it wasn't, actually, looking at the clock, that was four hours ago. Time flies when you're having fun. <p> My shack is the centre of my radio activities. I might receive a gadget from a friend to test and I'll put it on my desk ready to go. The same is true for a foot pedal that I found when looking for something else, as is the audio adaptor that I used in the desk mixer that I'm experimenting with. <p> Over time each of these bits and pieces accumulate on the surface. <p> When I noticed that my radio was running hot, or in my mind uncomfortably warm, given that I'm using 5 Watts, I decided to invest in a fan, clipped to the edge of the desk requiring yet another wire. <p> It's not limited to small bits. I'm testing a new radio, that comes with removable head, a microphone, cables to join those to the main body, two antenna port cables, a coax switch and a power lead with two cables. <p> Over time you have coax mixed with 12 Volt DC and 240 Volt AC, audio leads, USB leads, video leads, grounding wire, remote control switches, microphone leads, CAT leads and more, all running all over the place. <p> Making a minor change can become a big hassle, making it hard to determine what goes where, not to mention that each cable generates it's own little slice of RF, wanted or not. <p> The four hours I've just spent consisted of taking everything except the bolted on computer monitors off the desk and starting from scratch. <p> I also did this when I first added a second radio, but that was so long ago that the "system" I implemented then was unrecognisable. Doing it again today I made better use of the environment and changed some things around. I started with the 240 Volts requirements, then the coax, then 12 Volts, then audio and finally USB, using cable ties for semi-permanent things like power boards and hook and loop straps for things that move more frequently like audio wiring and video cables. <p> It's not perfect. I'm looking for some flexible coax patch leads, there's USB cables going every which way, the laptop keyboard isn't used, so why use a laptop, no doubt I'll discover more. <p> My point is that this is dynamic and every now and then it pays to spend a little while putting things back together. <p> My next project is to use an audio mixer to bring all the audio together in one place so I can use one headset for everything and give me the opportunity to plug in a tape recorder as my regulator suggests for monitoring emergency communications, though I might have to come up with something a little less 1980 for the actual recording. <p> If you're going to do this, move the desk at least a meter from the wall so you can get at the back of your shack, you can thank me later. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

When you just have to try things ...
Foundations of Amateur Radio <p> A little while ago I was gifted a new radio, well, new to me. A Kenwood TS-480HX. It's an all mode HF transceiver with 6m. Does 200 Watts, but you know me, I'm into QRP, low power, so I first had to figure out how to dial the transmitter down to 5 Watts and that was after figuring out how to feed the dual power supplies from one source and have the fuses work as expected. <p> When I received the radio, I took stock of all the bits that it was packed with, all complete, all the accessories, even the user manual was laminated. The previous owner, Walter VK6BCP (SK) whom I never met was an amateur after my own heart. I've talked about how he meticulously documented his alterations to a power supply for example. <p> Previously I've taken this radio on holidays to operate portable in a field day. The experience was underwhelming, in that I didn't hear anyone and nobody responded to my CQ calls. At the time I put it down to a poor antenna and unfamiliarity with the radio, despite reading the manual, well, at least scanning it. <p> Today I finally set some time aside to do some more testing. I decided that the first step would be to actually set it up in my shack, next to my trusty Yaesu FT-857d and see how it performs in comparison. <p> So, I plugged everything in, found a coax switch so I could switch the antenna between the two radios and learned that the audio connector that I've been using for digital modes on the Yaesu is actually compatible with the Kenwood. Now I need to make another adaptor for this radio, but in the meantime I can move the audio plug between radios when I swap. <p> In doing this I learnt a few things. <p> One is that there's plenty of scope for things to break. <p> For example, I was reaching over the desk to plug a connector into the coax switch when I leaned on the keyboard and touched the space bar. This caused the radio that I was working on to start its tuning cycle without an antenna connected. Fortunately I was using 5 Watts and I caught it within seconds, so no white smoke this time around. <p> It does remind me to turn off the radio when fiddling with connectors though. I'm embarrassed to report that I thought I'd learnt that lesson already, nothing like a refresher course in transmitter safety and dumb things not to do in the shack. <p> Then there was the thing about using remote control. In my naivety I thought that the connector that the Yaesu uses for computer control is also used on the Kenwood. Turns out that it isn't. Fortunately I read the manual before plugging that in. <p> The Yaesu has a specific digital mode with individual gain and filter characteristics, which seem to be completely lacking on the Kenwood. <p> I'm still attempting to learn the differences in receive performance between the two. I started this process by running WSJT-X and listening to WSPR or Weak Signal Propagation Reports and testing how both radios decode things. I cannot yet do this side-by-side, but for now I can swap and see signals coming in on either radio. <p> This is not the first time I've put a different radio on my desk to see how it works and it's not going to be the last time. What I'm looking to achieve is to swap over from the Yaesu to the Kenwood in my shack, so I can put the Yaesu back in the car and have a mobile shack operating again because I have to admit, I do miss that. <p> What kinds of testing regimes to you have when you're trying out a new radio? I'd love to hear your thoughts. My email address as always is cq@vk6flab.com. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Portable experiences ...
Foundations of Amateur Radio <p> Last weekend was memorable for all the right reasons. Filled with 24 hours of amateur radio, spent with friends, in a park, making noise and having fun, marking the first time I recall setting up in a park for that length of time with so few extra resources. Normally we'd be decked out with tents, or in my case a swag, we'd have camping stoves, perhaps even a caravan or two, tables, cutlery, the whole shebang. <p> This time we brought none of that. Just radios, antennas, batteries, water with a few snacks and folding chairs. <p> This was like nothing I've experienced before and it has me asking myself: Why did I wait so long to operate like this? <p> It was wonderful. <p> We spent it being on-air and making noise during a 24 hour contest which is specifically intended to celebrate and reward portable operation. In case you're wondering, the John Moyle Memorial Field Day is to encourage portable field day operation and provide training for emergency situations. It was created in memory of John Moyle, the long term editor of Wireless Weekly, who served in the RAAF with distinction. He's said to be responsible for a number of innovative solutions to keeping radio and radar equipment working under difficult wartime conditions. <p> I've participated in this contest plenty of times before. This was the first time I did it in a park, in the city, and as experiences went it was fabulous and recommended. <p> As you might know, I like operating portable. I've been operating from my car for years, from camp-sites in remote locations for just as long and I've activated several parks and peaks in Summits On The Air, or SOTA, and World Wide Flora and Fauna, or WWFF activities. I've also set-up during field days in local parks and I regularly drive to a local park to get on-air and make noise. With that as background, you might ask yourself, what is different? <p> Let's start with setting the scene. <p> The park that we used is located in a suburb about 10 km out from the city centre. It has a river running through it and on the banks there are plenty of trees with lawn. Dotted throughout are picnic tables with wooden gazebos. All very civilised. <p> From a radio perspective, it was RF quiet, that is, no local electrical noise, away from cars, from a footpath, close enough to parking where we could get our gear out of the car and walk it to the site. <p> All that alone would have made for a great experience, but this went beyond that. <p> For example, dinner consisted of ordering from the local fish and chips shop five minutes away and picking up some amazing seafood. While there collecting some extra water and most importantly dessert from the supermarket next door. <p> During our activities we had visits from local amateurs. Over the 24 hours we had a steady stream of interested hams coming out and having a chat. Some took the opportunity to bring food, dips and crackers, thermos flasks of tea, even ice cold beer. One amateur came along at the end of our activation and helped pack-up. All this made for a very enjoyable social experience. <p> Another thing that was different was that the operator could wear headphones without stopping anyone else from hearing what was going on. We achieved that by connecting a headphone splitter to the radio, piping the audio to some external speakers for local monitoring whilst the operator wearing headphones would not be affected by conversations taking place around them. <p> We did have some challenges. <p> Our logging tool of choice was, for reasons we don't yet understand, switching bands which meant that sometimes the numbers we were giving out were not sequential. Generally in a contest situation you exchange a piece of information in addition to a signal report. In this case it's supposed to be a sequential number and because there were multiple operators, the sequence is supposed to be per band. <p> The trees provided shade, but were not quite up to the task of being sky-hooks able to hold up wire antennas, fortunately we brought squid poles for that purpose. <p> It was hot. 38 degrees Celsius. It turns out that even though wearing a black long-sleeve T-shirt is not a suitable fashion choice from a temperature perspective, it was perfect in preventing sunburn and for that I was immensely grateful. <p> As you might know, we track what we bring in a spreadsheet, one row per item. A column for each time we go out. Over time we learn what's used and what's not. Our list is getting better and better. <p> I'll admit that I felt some trepidation in relation to this location, but I'm so glad that I took a leap of faith and went with the experience. <p> What a blast! <p> What kind of activities have you been up to that gave you a blast? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The remote edge...
Foundations of Amateur Radio <p> The landscape of remotely operated amateur radio is changing by the day. Once the territory of home brew DTMF decoders and remote controlled radio links, now more often than not it's a Raspberry Pi with an internet connection, or some variation on that. <p> Before I continue, I must point out that amateur regulations vary widely around the globe, especially in this area. It appears mostly due to the rapidly changing nature of remotely operated radios. <p> For example, most, if not all software defined radios are technically remotely operated. You run software on your computer, the radio is connected to a network, you twiddle a setting on your computer and the radio responds. The computer is not part of the radio, but without it there's not much radio to be had. There's no need for both to be in the same room, let alone the same building. <p> Similarly, a Kenwood TS-480 and a Yaesu FT-857d are both radios that have a removable face with knobs and a display. The main body of the radio is a nondescript box with sockets for power and antenna, connected to the face essentially via a serial cable that can be a few centimetres long, or a few meters. There's solutions like RemoteRig that replace this serial cable with a virtual cable, allowing you to put the face in one location and the body in a different one, connected to each other across the internet. <p> With the introduction of Starlink internet, a low earth orbit satellite based network, a connection to the internet can be made anywhere on earth, making it possible to have your station sitting somewhere far away from interference, powered by batteries and solar panels and connected to the internet. You might not even need to go to satellite based internet, the mobile phone network in many places is often more than sufficient for making such a station viable. <p> If you're a member of a radio club, you might consider your club station. Often this station is the work of many volunteer years effort with multiple radios, antennas, filters and the like and often it sits idle most of the time, only getting fired up during club meetings or the weekend. What if you connected that station to the internet and offered it as a service to your members? <p> Depending on license requirements, you might consider amateurs who have limited ability to build a shack but would love to be on air making noise. A remote club shack might be just the ticket for getting them on air. It could even become an income stream for your club. <p> You might be able to offer access to trainees, or let them monitor the station without transmit ability whilst they're preparing for their license, or you might operate a 48 hour contest in shifts, all using the same transmitter, but from the comfort of your home. <p> The landscape is full of different solutions, like RemoteRig, which I've already mentioned, RigPi Remote Station Server is a tiny computer that controls your radio and allows you access via a web browser or remote desktop connection. There's Remote Hams, a ready made solution for putting your shack on air with access control and remote management. You can connect specific radios, like the Elecraft K3 Remote System, or a Flex Radio Maestro, there's even web browser remote control projects like Universal Ham Radio Remote by Oliver F4HTB, each making it possible to get on air and make noise using a radio in a different location across the internet. <p> All of the solutions I've named make it possible to fully use your radio, that means CW, SSB, FM, antenna control and the like. You can use it for FT8 or RTTY, the choice is yours. <p> The interface might be the face of your radio, a special console, computer, phone or a tablet and you can operate it wherever and whenever the mood takes you. <p> No longer do you need to have a shack in your home with coax snaking through the walls to an antenna whilst dodging the local authorities, or fighting the engine noise from your car. You can make the ultimate shack anywhere without taking up space in your home or car. <p> One final comment. This is a moving feast. The level of functionality is increasing by the day. For me this journey started with a steel toolbox in my garage with a radio inside it and coax running from the box to my antenna. I have operated my radio and hosted my weekly net like this. The radio in the garage, me in my office connected via Wi-Fi over a virtual serial cable. You don't need to start this in the middle of nowhere, six hours drive over the back roads to fix a problem, you can start this project today at home. <p> Where on this journey are you and what issues have you come up against? Let me know. My address as always is cq@vk6flab.com <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Making observations
Foundations of Amateur Radio <p> Amateur radio is an environment for infinite possibilities. I've spoken about the way that contacts can happen, seemingly out of the blue, how propagation has so many variables it's hard to predict what will happen at any given moment. During a contest you might scan up and down the bands looking for an elusive multiplier, a contact that's worth extra points, or a missing DXCC country, in your quest to contact a hundred or more. It's easy to get swept away in the excitement and disappointment that comes with success and failure. <p> I'm mentioning this because it's pretty much how many people in our community go about their hobby, me included. <p> I've likened making a contact to fishing, taking your time to get the rhythm of the other station, understanding that there's a human at the other end. Taking stock of what they're hearing, which stations they're responding to, how they respond and if they give out hints about making a successful contact with them. <p> The other day I came across a request to decode some Morse on an image showing long and short lines joined together in some form to serve an artistic purpose. Others pointed out that this wasn't Morse. I took an extra moment to point out that Morse had four individual attributes. It has a dit, a dah, a spacing between the letters and a spacing between the words, and since this image didn't have that it couldn't be Morse code. A few days later it occurred to me that I hadn't been paying attention. Morse actually has five attributes, it also has a spacing between each tone. I updated my answer and began to think about this interaction. <p> It's not the first time that I've stopped to consider what's happening. <p> For example, if I change bands on FT8, a digital mode that is very helpful for determining current propagation, I have a look at the level of activity. I'm generally not in a hurry, so I tend to leave it on the same band for a while, sometimes an hour, sometimes less, sometimes more. If the band is in full flight with every slot filled, it's easy to tick the "CQ Only" box and hide all the noise, or rather extra messages that form the exchange, but sometimes that noise has a whole lot of interesting information. <p> You can determine if one of the stations calling CQ is actually answering anyone or if they're just an alligator, all mouth, no ears. You can see individual people attempting to get each other's attention, making a local or a long distance contact. You can type in an interesting grid locator that accompanies most CQ calls and see just how far it is from you and in which direction. <p> I will also point out that using FT8 to observe a so-called dead band can be just as illustrative. It allows you to see signals in the waterfall, it decodes things that are barely visible and it will give you a feel for how your station at that location on that band at that time is performing in real-time. For example, it showed me that the squelch on my radio was turned on and blocking any chance of receiving weak signals, something that I wouldn't have noticed if I hadn't taken the time to observe. <p> Another example. During a contest I often take some time to listen to a pile-up that surrounds a massive station to see what stations I can hear, who is coming in strong and who is coming in weak. I keep a mental or actual note of what cracks the S-meter with an indication of signal strength and what only turns up as audio, perfectly readable, but not exciting the needle in any way. I might not speak with any of those stations, but I know that there are stations in a particular location that I can hear. <p> It's easy to get swept up in all this massive excitement that is our hobby, but sometimes it pays off to take a breath, to wait a moment, to take a look and have a listen to learn the lay of the land and understand what is happening and consider the implications. Within that moment of calm you might find an unexpected jewel in the rough. That's for example how I managed a contact with South Sudan several years ago during a massive pile-up in a club station during a contest. <p> I'd love to hear what you have stumbled upon serendipitously like that. You can always get in touch, cq@vk6flab.com is my address. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Word of the day: software
Foundations of Amateur Radio <p> Every community has its own language. As a member of that community you learn the words, their meaning and their appropriate use. For example, the combination of words "Single Side Band" have a specific meaning inside amateur radio. Outside of radio, those same words are random words with no relationship. <p> Sometimes a term like "FM" can be heard across many communities with similar understanding, though not identical. <p> It gets tricky when a word is used widely but doesn't have a common understanding at all. A word like "software" for example. <p> A question you might hear in amateur radio is: "Can I buy a software defined radio or SDR that has digital modes built-in?" <p> It's a perfectly reasonable question, the radio runs software, the digital modes are software, so the answer is obvious, right? <p> What about: "Can the hundred or more computers in my car play Solitaire?" <p> Aside from the perhaps unexpected fact that your car has computers on board, you most likely know the answer to that. No, since the computers are specialised for different tasks - and if you're driving a Tesla right now, yes, you can play Solitaire, but I'd recommend that you keep your eyes on the road instead. <p> My point is that not all software is created equal. <p> The software inside an SDR is essentially doing signal processing, often by several components, each running software, transforming an antenna signal into something, that can be used somewhere else, likely sound. <p> The applications WSJT-X and fldigi, both software, use a computer running Linux, MacOS or Windows, software, to decode and encode digital modes while providing a way for you to interact with it. Software running on software. <p> You might well argue that we should be running applications like that directly on our radio and on the face of it that sounds perfectly reasonable, except that to achieve that, you'd also need to build a system to install and update different types of applications, so you could run SSTV, APRS, RTTY, PSK31, FT8 or any of the other hundreds of digital modes and new ones as they are developed. <p> If you did that, you'd also have to provide a way to manage the operating system, to connect to the Internet and provide security. You'd need to develop a user-interface, perhaps a keyboard and mouse solution, a screen, etc. <p> Before long you'll have developed a whole computing infrastructure, much like the one we already have in the form of the computer on your desk or the phone in your pocket. <p> Computers are getting faster and faster every day. This allows for the software on them to become more and more complex. The inter-dependencies are increasing by the second, but that doesn't mean that specialisation isn't useful. <p> A software defined radio likely has a Field Programmable Gate Array, an FPGA on-board that is great at processing data in streams. It too runs software. Your microwave is running software, as is your television, your smart-watch, your battery charger, the gearbox in your car and your electric tooth brush. <p> Making a distinction between the various types of software is helpful to understand what is possible and what is not. Being a computer nerd, I must point out that I've only barely scratched the surface of software here, in-case you're curious, microcode, firmware, hardware abstraction, the rabbit hole goes very deep. <p> Not all software is created equal and every now and then it's a good idea to remember that when you talk about a word in one community, it might mean a completely different thing in another and sometimes the distinction is significant. <p> As for having an SDR that runs WSPR, no. You can transmit from a computer though, but that's a whole other thing. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How many hops in a jump?
Foundations of Amateur Radio <p> Amateur radio lives and dies with the ionosphere. It's drilled into you when you get your license, it's talked about endlessly, the sun impacts on it, life is bad when the solar cycle is low and great when it's not. There's sun spots, solar K and A indices, flux, different ionosperic bands and tools online that help you predict what's possible and how likely it is depending on the time of day, the frequency, your location and the curent state of the sun. If that's not enough, the geomagnetic field splits a radio wave in the ionosphere into two separate components, ordinary and extraordinary waves. <p> All that complexity aside, there's at least one thing we can all agree on. A radio wave can travel from your station, bounce off the ionosphere, come back to earth and do it again. This is known as a hop or a skip. If conditions are right, you can hop all the way around the globe. <p> I wanted to know how big a hop might be. If you know that it's a certain distance, then you can figure out if you can talk to a particular station or not, because the hop might be on the earth, or it might be in the ionosphere. Simple enough right? <p> My initial research unearthed the idea that a hop was 4000 km. So, if you were attempting to talk to a station at 2000 km or at 6000 km you couldn't do that with a hop of 4000 km. <p> If you've been on HF, we both know that's not the case. <p> If you need proof, which you really should be asking for, you should check out what the propagation looks like for any FT8 station, or any WSPR beacon over time and you'll notice that it's not 4000 km. <p> Just like the crazy network of interacting parameters associated with propagation, the distance of a hop can vary, not a little, but a lot. <p> In 1962, in the Journal of Geophysical Research D.B. Muldrew and R.G. Maliphant contributed an article titled: "Long-Distance One-Hop Ionospheric Radio-Wave Propagation". They found that in temperate regions such a hop might be 7500 km and in equatorial regions even 10,000 km. <p> I'm mentioning this because this was based on observations and measurements. <p> They used frequency sweeps from 2 to 49 MHz though they called them Mega Cycles, using 100 kHz per second, that is, over the duration of a second, the frequency changed by 100 kHz, so each sweep took nearly 8 minutes using only 15 kilowatts, so substantial gear, not to mention expense and availability. <p> Oh, computers, yes, they used those too. A three tonne behemoth called an IBM 650, mind you, that's only the base unit, consisting of a card reader, power supply and a console holding a magnetic drum unit. <p> You know I'm going somewhere with this right? <p> Today, you can do the same measurements with a $5 computer and a $20 receiver. For a transmitter, any HF capable radio will do the trick, though you might not be transmitting long if you stray outside the amateur bands. For power, 5 Watts is plenty to get the job done. <p> My point is that there is a debate around the future of our hobby and why modes like FT8 are such a controversial topic in some communities. <p> I'm here to point out that since that publication in 1962 our hobby has made some progress and we can improve on the work done by people who came before us. We could build a glob-spanning real-time propagation visualisation tool, we already have the data and modes like FT8 keep feeding in more. <p> If you're inclined, you could even make such a plot in real-time for your own station. <p> So, how long is a hop? <p> You'll just have to find out. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

You Can't Always Get What You Want
Foundations of Amateur Radio <p> One of the things about amateur radio that I find intensely fascinating and to be honest sometimes just as frustrating, is that you don't know what the outcome of an experiment might be at any one time. Not because you cannot control the experiment, or because you don't know what you're doing, but because the number of variables involved in most meaningful amateur radio experiments is pretty much infinite. <p> I've spoken about this before, the idea that if you were to make a simple dipole antenna and fold the ends on each other, you'd have infinite variation in antennas with just a so-called simple antenna, since you can vary the shape of it in an unending variety of ways. <p> The other day I was doing an experiment. An amateur radio one to be sure, but I was doing this within the realm of computing. I have been playing with digital modes for some time now and along the way shared some of what I've learnt. It occurred to me that I've been assuming that if you had the chance to follow along, you'd have access to the required hardware, simple enough, a $20 RTL-SDR dongle, but none-the-less, extra hardware. <p> What might happen if you rule out that dongle and instead used a web-based receiver like WebSDR, or KiwiSDR, or any number of other such sites where you can pretty much tune to any band and frequency and see what's going on at a particular antenna location. <p> For one it might allow you to decode something like APRS remotely, or decode an FT8 signal, perhaps even your own FT8 signal. Unfortunately most, if not all, of those sites include only the bare bones decoders for things like CW, AM, SSB and FM. After that you're pretty much on your own. <p> You could do some funky stuff with a web-browser, linking it via some mechanism to the tool you use to actually decode the sound and there's some examples of that around, none that I really warmed to, since it requires that I open a web browser, do the mouse-clicky thing and then set-up some audio processing stuff. <p> What if I wanted to figure out where the ISS was right now and wanted to listen to a receiver that was within the reception range of the ISS as it passed overhead, and automatically updated the receiver in real time as the ISS was orbiting the earth? <p> For that to happen you'd need something like a command-line tool that could connect to something like a KiwiSDR, tune to the right frequency and extract the raw data that you could then decode with something appropriate. <p> Turns out that I'm not the first person to think of this. There's even a project that outlines the idea of following a satellite, but it hasn't moved anywhere. <p> There's also a project that is a command-line client for web-based KiwiSDR sites, but after spending some quality time with it and its 25 clones on github, I'm not yet at the point where this will work. Mainly because the original author made a design decision to record data to a file with a specific name and any clone I've found thus far only allows you to define what name to use. None so far actually appear to send their stream to something that can be processed in real time. <p> Of course I could record a few minutes of data and process that, but then I'd have to deal with overlap, missing data, data that spans two files and a whole host of other issues, getting me further and further away of what I was trying to do, make a simple web-based audio stream digital mode decoder. <p> As the Rolling Stones put it, "You Can't Always Get What You Want" <p> And to me this sums up our hobby in a nutshell. When you call CQ, or go portable, or test an antenna, or attempt to build something new, there's going to be setbacks and unexpected hurdles. <p> I think that it is important to remember that amateur radio isn't finished, it's not turn-key, no matter how much that appeals, you cannot find a one size fits all solution for anything, not now, not yesterday and not tomorrow. <p> This hobby is always going to test boundaries, not only of physics, but your boundaries. It's after all one giant experiment. <p> So, next time you don't get what you want, you might try something you find, and get what you need. <p> Also, apologies to Keith Richards and Mick Jagger for butchering their words, a rockstar I am not. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Running out of things to do ...
Foundations of Amateur Radio <p> So, there's nothing on TV, the bands are dead, nobody is answering your CQ, you're bored and it's all too hard. You've run out of things to try, there's only so many different ways to use the radio and it's all too much. <p> I mean, you've only got CW, AM, SSB, FM, there's Upper and Lower Side-band, then there's RTTY, the all too popular FT8, then there's WSPR, but then you run out of things. I mean, right? <p> What about PSK31, SSTV, then there's AMTOR, Hellschreiber, Clover, Olivia, Thor, MFSK, Contestia, the long time favourites of Echolink and IRLP, not to forget Fusion, DMR, D-STAR, AllStar, BrandMeister or APRS. <p> So far I've mentioned about 20 modes, picked at random, some from the list of modes that the software Fldigi supports. Some of these don't even show up on the Signal Wiki which has a list of about 70 amateur modes. <p> With all the bands you have available, there's plenty of different things to play with. All. The. Time. <p> There's contests for many of them, so once you've got it working, you can see how well you go. <p> Over the past year I've been experimenting with a friend with various modes, some more successful than others. I'm mentioning this because it's not difficult to get started. Seriously, it's not. <p> The most important part of this whole experiment is getting your computer to talk to your radio. If you have FT8 already working you have all the hardware in place. To make the software work, you can't go past installing Fldigi. As a tool it works a lot like what you're familiar with. You'll see a band-scope, a list of frequencies and a list of decodes. It's one of many programs that can decode and generate a multitude of amateur digital modes. <p> If this is all completely new to you, don't be alarmed. <p> There are essentially two types of connections between your computer and your radio. The first one is audio, the second is control. For this to work well, both these need to be two-way, so you can both decode the audio that the radio receives and generate audio that the radio can transmit. The same is true for the control connection. You need to be able to set the transmit frequency and the mode and you need to be able to read the current state of the radio, if only to toggle the transmitter on-and-off. If you already have CAT control working, that's one half done. <p> I've spoken with plenty of amateurs who are reluctant to do any of this. If this is you, don't be afraid. It's like the first time you keyed up you radio. Remember the excitement? You can relive that experience, no matter how long you've been an amateur. <p> Depending on the age of your radio, you might find that there is only one physical connection between your computer and the radio, either using USB or even Ethernet. You'll find that your computer will still need to deal with the two types of information separately. <p> Notice that I've not talked about what kind of operating system you need to be running. I use and prefer Linux, but you can do this on any operating system, even using a mobile phone if that takes your fancy. <p> Getting on air and making noise using your microphone is one option, but doing this using computer control will open you to scores of new adventures. <p> I will add some words of caution here. <p> In general, especially using digital modes, less is more. If you drive the audio too high you'll splatter all over the place and nobody will hear you, well, actually, everyone will, but nobody will be able to talk to you because they won't be able to decode it. If the ALC on your radio is active, you're too loud. WSJT-X, the tool for modes like FT8 and WSPR, has a really easy way of ensuring that your levels are right, so if you've not done anything yet, start there. <p> Another issue is signal isolation. What I mean by that is you blowing up your computer because the RF travelled unexpectedly back up the serial or audio cable and caused all manner of grief. You can get all fancy with optical isolation and at some point you should, but until then, dial the power down to QRP levels, 5 Watts, and you'll be fine. <p> A third issue that was likely covered during your licensing is the duty cycle. It's the amount of time that your radio is transmitting continuously as compared to receiving only. For some modes, like WSPR for example, you'll be transmitting for a full 2 minutes at 100%, so you'll be working your radio hard. Even harder might unexpectedly be using FT8, which transmits in 15 second bursts every 15 seconds, so there may not be enough time for your radio to cool down. Investing in a fan is a good plan, but being aware of the issue will go a long way to keeping the magic smoke inside your radio. <p> I'm sure that you have plenty of questions after all that. <p> You can ask your friends, or drop me an email, cq@vk6flab.com and I'll be happy to point you in the right direction. <p> Next time there's nothing good on TV, get on air and make some digital noise! <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What's in a prediction?
Foundations of Amateur Radio <p> Over the past little while I've been experimenting with various tools that decode radio signals. For some of those tools the signals come from space. Equipment in space is moving all the time, which means that the thing you want to hear isn't always in range. <p> For example. <p> The International Space Station or ISS has a typical orbit of 90 minutes. Several times a day there's a pass. That means that it's somewhere within receiving range of my station. It might be very close to the horizon and only visible for a few seconds, or it might be directly overhead and visible for 10 minutes. If it's transmitting APRS on a particular frequency, it can be decoded using something like multimon-ng. If it's transmitting Slow Scan TV, qsstv can do the decoding. I've done this and I must say, it's exciting to see a picture come in line-by-line, highly recommended. <p> The National Oceanic and Atmospheric Administration or NOAA, has a fleet of satellites in a polar orbit that lasts about 102 minutes and they're overhead at least every 12 hours. You can use something like noaa-apt to decode the images coming from the various weather satellites, or a python script and I'll talk about that at some point. <p> There is a growing cloud of cube satellites with interesting telemetry. They're in all kinds of orbits and you can attempt to receive data from each one as it's in sight. <p> Keeping track of what's where and when is a full time job for plenty of people. As a radio amateur I'm happy to defer to the experts who tell me where a piece of equipment is and when I'm likely to be able to receive a radio signal from the transmitter I'm interested in. <p> Previously I've mentioned in passing a tool called gpredict that does this heavy lifting for me. It presents a map of the world and shows what's visible at my location and when the next acquisition of signal for a particular satellite might occur. It talks to the internet to download the latest orbital information. It also has the ability to control a rotator to point your antenna, not that I have one, and it can update the transmit and receive frequency of your radio to compensate for the Doppler effect that changes the observed frequency as a satellite passes overhead. All this works with a graphical user-interface, that is to say, you have a screen that you're looking at and can click on. <p> Whilst running gpredict, you can simultaneously launch the appropriate decoding tool for the signal that you're trying to receive. If you have a powerful enough computer, you can run multiple decoding tools together. You'll have separate windows for controlling the radio and antenna, for decoding APRS, SSTV, NOAA and if you're wanting to do sunrise and sunset propagation testing using WSPR, you can also run WSJT-X or any other decoder you're interested in. <p> There are some implications associated with doing this, apart from needing a big enough screen, needing considerable computing power and burning electricity for no good reason, the signal that comes in from your radio will be fed to all the decoders at the same time and all of them will attempt to decode the signal, even when you know that this serves no purpose. That's fine if you don't know what you're listening to, but most of the time you know exactly what it is, even if the software doesn't. <p> Manually launching and quitting decoders is one option, but what if the next ISS pass is at 3am? <p> Aside from the computing requirements, so far this works fine with a standard analogue radio like my Yaesu FT-857d. The only limitation is that you can only receive one station at a time. <p> If you replace the analogue radio with an RTL-SDR dongle, you gain the ability to record and decode simultaneous stations within about 2.4 MHz of each other. <p> Another option is to use an ADALM Pluto and as long as the stations are within 20 MHz of each other, you can record and decode their signals. If you're not familiar with a Pluto, it's essentially a computer, receiver and transmitter, all in a little box, the size of a pack of cards. <p> This is where it gets interesting. <p> The Pluto doesn't have a screen, or a keyboard for that matter, but it's a computer. It runs Linux and you can run decoders on it. I've done this with ADS-B signals using a tool called dump1090. You'll find it on my GitHub page. <p> One of the sticking points in decoding signals from space was the ability to predict when a satellite pass occurs without requiring a computer screen. Thanks to a command-line tool called "predict", written by John, KD2BD and others I've now discovered a way to achieve that. My efforts are not quite at the point of show-and-tell, but I've got a Docker container that's building and running predict on its own and using a little bash script it's telling me when the ISS is overhead. You'll find that on GitHub as well. <p> My next challenge is to do some automated decoding of actual space signals. I'm going to start with the ISS, predict and multimon-ng. I'll let you know how I go. <p> What space signals are you interested in? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Changing of the guard ...
Foundations of Amateur Radio <p> When you begin your journey as a radio amateur you're introduced to the concept of a mode. <p> A mode is a catch-all phrase that describes a way of encoding information into radio signals. <p> Even if you're not familiar with amateur radio, you've come across modes, although you might not have known at the time. <p> When you tune to the AM band, you're picking a set of frequencies, but also a mode, the AM mode. When you tune to the FM band, you do a similar thing, set of frequencies, different mode, FM. The same is true when you turn on your satellite TV receiver, you're likely using a mode called DVB-S. For digital TV, the mode is likely DVB-T and for digital radio it's something like DAB or DAB+. <p> Even when you use your mobile phone it too is using a mode, be it CDMA, GSM, LTE and plenty of others. <p> Each of these modes is shared within the community so that equipment can exchange information. Initially many of these modes were built around voice communication, but increasingly, even the basic mobile phone modes, are built around data. Today, even if you're talking on your phone, the actual information being exchanged using radio is of a digital nature. <p> Most of these modes are pretty static. That's not to say that they don't evolve, but the speed at which that happens is pretty sedate. <p> In contrast, a mode like Wi-Fi has seen the explosion of different versions. During the first 20 years there were about 19 different versions of Wi-Fi. You'll recognise them as 802.11a, b, g, j, y, n, p, ad, ac and plenty more. <p> I mention Wi-Fi to illustrate just how frustrating changing a mode is for the end-user. You buy a gadget, but it's not compatible with the particular Wi-Fi mode that the rest of your gear is using. <p> It's pretty much the only end-user facing mode that changes so often as to make it hard to keep up. As bad as that might be, there is coordination happening with standards bodies involved making it possible to purchase the latest Wi-Fi equipment from a multitude of manufacturers. <p> In amateur radio there are amateur specific modes, like RTTY, PSK31, even CW is a mode. And just like with Wi-Fi, they evolve. There's RTTY-45, RTTY-50 and RTTY-75 Wide and Narrow, when you might have thought that there was only one RTTY. The FLDIGI software supports 18 different Olivia modes out of the box which haven't changed for a decade or so. <p> The speed of the evolution of Olivia is slow. The speed of the evolution of RTTY is slower still, CW is not moving at all. At the other end new amateur modes are being developed daily. <p> The JT modes for example are by comparison evolving at breakneck speed, to the point where they aren't even available in the latest versions of the software, for example FSK441, introduced in 2001 vanished at some point, superseded by a different mode, MSK144. It's hard to say exactly when this happened, I searched through 15 different releases and couldn't come up with anything more definitive than the first mention of MSK144 in v1.7.0, apparently released in 2015. <p> My point is that in amateur radio terms there are modes that are not changing at all and modes that are changing so fast that research is being published after the mode has been depreciated. Mike, WB2FKO published his research "Meteor scatter communication with very short pings" comparing the two modes FSK441 and MSK144 in September 2020, it makes for interesting reading. <p> There are parallels between the introduction of computing and the process of archiving. The early 1980's saw a proliferation of hardware, software, books and processes that exploded into the community. With that came a phenomenon that lasted at least a decade, if not longer, where archives of these items don't exist because nobody thought to keep them. Floppy discs thrown out, books shredded, magazines discarded, knowledge lost. <p> It didn't just happen in the 1980's. Much of the information that landed man on the moon is lost. We cannot today build a Saturn V rocket with all the support systems needed to land on the moon from scratch, even if we wanted to. We have lost manufacturing processes, the ability to decode magnetic tapes and lost the people who did the work through retirement and death, not to mention company collapses and mergers. <p> Today we're in the middle of a golden age of radio modes. Each new mode with more features and performance. In reality this means that your radio that came with CW, AM, FM and SSB will continue to work, but if it came with a specialised mode like FSK441, you're likely to run out of friends to communicate with when the mode is depreciated in favour of something new. <p> In my opinion, Open Source software and hardware is vitally important in this fast moving field and if we're not careful we will repeat history and lose the knowledge and skill won through perseverance and determination due to lack of documentation or depreciation by a supplier. <p> When did you last document what you did? What will happen to that when you too become a silent key? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The Vagabond HAM
Foundations of Amateur Radio <p> This podcast began life under the name "What use is an F-call?" and was renamed to "Foundations of Amateur Radio" after 206 episodes. To mark what is effectively this, the 500th episode, I considered a retrospective, highlighting some of the things that have happened over the past decade of my life as a radio amateur. I considered marking it by giving individual credit to all those amateurs who have helped me along the way by contacting me, documenting things, asking questions, sharing their experiences or participating in events I attended. Whilst all these have merit, and I should take this opportunity to thank you personally for your contribution, great or small, to amateur radio, to my experience and that of the community. Thank you for making it possible for me to make 500 episodes, for welcoming me into the community, for being a fellow amateur. Thank you. <p> During the week I received an email from Sunil VU3ZAN who shared with me something evocative with the encouragement to bring it the attention and appreciation it deserves. <p> By way of introduction, on the 13th of June 2002, Ken, W6NKE became a silent key. Ken was an amateur, an active one by all accounts. I never met Ken, but his activity list is long and varied. Ken became interested in ham radio as a teenager in the 1930s. He was a long time advocate of CW and during WWII he taught Morse code to Navy operators. In 1975 he founded The Sherlock Holmes Wireless Society and was editor of its newsletter, now called "The Log of the Canonical Hams". He received his Investiture from The Baker Street Irregulars in 1981. Ken was an early member of the International Morse Preservation Society or FISTS, he held number 0818. He was the President of Chapter 2 of the Old Old Timers Club, the OOTC for many years. In addition to drawing cover art, Ken also wrote. Lots. 73 magazine features plenty of Ken's articles with titles like: "Inexpensive Vertical", "Don't Bug me Dad" and "The DX Hunter". <p> Ken was also a poet, which brings us to the way that I think is appropriate to mark the 500th episode of this podcast. I'm confident that you can relate to this contribution by Ken to amateur radio, published in Volume 1, Number 3 of 73 magazine in December 1960. <p> <p> The Vagabond HAM, by Ken Johnson W6NKE (SK) <p> A vagabond's life is the life I live Along with others, ready to give A friendly laugh and a word of cheer To each vagabond friend, both far and near. <p> I travel the air waves, day or night To visit places I'll never sight From the rail of a ship, or from a plane Yet I'll visit them all again and again. <p> I never hear from a far off land That my pulse doesn't quicken. With careful hand I tune my receiver and VFO dial To make a new friend and chat for awhile. <p> Africa, Asia, they're all quite near In as easy reach as my radio gear With the flip of a switch, the turn of a knob I can work a ZL, a friend named Bob. <p> There's an LU4, a fellow that's grand Who's described to me his native land 'Till I can hear the birds, and feel the breeze As it blows from the slopes of the mighty Andes. <p> I learned of the surf, and a coral strand, The smell of hybiscus where palm trees stand 'Neath a tropical moon, silver and bright From an FO8 that I worked one night. <p> I've thrilled to the tales of night birds' screams In the depths of the jungle where death-laden streams Flow'neath verdant growth of browns and greens From a DU6 in the Philippines. <p> The moors of Scotland, a little French Shrine, German castles on the River Rhine Of these things I've learned, over the air Without ever leaving my ham shack chair. <p> There's a KL7 on top of the world To whom the Northern Lights are a banner unfurled That sweeps across the Arctic night Makes the frozen sky a thing of delight. <p> Tales of silver and gold and precious stones Ancient temples and molding bones Where the natives, I'm told, are tall and tan By an XE3 down in Yucatan. <p> My vagabond trips over the air Will take me, well, just anywhere Where other vagabonds and I will meet From a tropical isle, to a city street. <p> My vagabond's life will continue, I know Through the fabulous hobby of ham radio And one day from out at the world's end We'll meet on the air, my Vagabond friend. <p> <p> <p> I'm Onno VK6FLAB <p> Note: The spelling of the poem is as published in 73 magazine.
Listen: podcast - audio/mp3

The APRS of it all ...
Foundations of Amateur Radio <p> Amateur radio is a living anachronism. We have this heady mix of ancient and bleeding edge, never more evident than in a digital mode called Automatic Packet Reporting System or APRS. It's an amateur mode that's used all over the place to exchange messages like GPS coordinates, radio balloon and vehicle tracking data, battery voltages, weather station telemetry, text, bulletins and increasingly other information as part of the expanding universe of the Internet Of Things. <p> There are mechanisms for message priority, point-to-point messages, announcements and when internet connected computers are involved, solutions for mapping, email and other integrations. The International Space Station has an APRS repeater on-board. You'll also find disaster management like fire fighting, earthquake and propagation reporting uses for APRS. There's tools like an SMS gateway that allows you to send SMS via APRS if you're out of mobile range. There's software around that allows you to post to Twitter from APRS. You can even generate APRS packets using your mobile phone. <p> In my radio travels I'd come across the aprs.fi website many times. It's a place that shows you various devices on the APRS network. You can see vehicles as they move around, radio repeater information, weather, even historic charts of messages, so you can see temperatures over time, or battery voltage, or solar power generation, or whatever the specific APRS device is sending. <p> As part of my exploration into all things new and exciting I thought I'd start a new adventure with attempting to listen to the APRS repeater on the International Space Station. I'm interested in decoding APRS packets. Seeing what's inside them and what kinds of messages I can hear in my shack. Specifically for the experiment at hand I wanted to hear what the ISS had to say. <p> After testing some recommended tools and after considerable time hunting I stumbled on multimon-ng. I should mention that it started life as multimon by Tom HB9JNX, which he wrote in 1996. In 2012 Elias Oenal wanted to use multimon to decode from his new RTL-SDR dongle and in the end he patched and brought the code into this century and multimon-ng was born. It's available on Linux, MacOS and Windows and it's under active development. <p> It's a single command-line tool that takes an audio input and produces a text output and it's a great way to see what's happening under the hood which is precisely what I want when I'm attempting to learn something new. <p> In this case, my computer was already configured with a radio. I can record what the radio receives from the computer microphone and I can play audio to the radio via the computer speaker. My magical tool, multimon-ng has the ability to record audio and decode it using a whole raft of in-built decoders. For my test I wanted to use the APRS decoder, cunningly disguised as an AFSK1200 de-modulator. I'll get to that in a moment. <p> The actual process is as simple as tuning your radio in FM mode to the local APRS frequency and telling multimon-ng to listen. Every minute or so you'll see an APRS packet or six turn up on your screen. <p> The process for the ISS is only slightly different in that the APRS frequency is affected by Doppler shift, so I used gpredict to change the frequency as required; multimon-ng continued to happily decode the audio signal. <p> I said that I'd get back to AFSK1200. The 1200 represents the speed, 1200 Baud. The AFSK represents Audio Frequency Shift Keying and it's a way to encode digital information by changing the frequency of an audio signal. One way to think of that is having two different tones, one representing a binary zero, the other representing a binary one. Play them over a loud-speaker and you have AFSK. Do that at 1200 Baud and you have AFSK1200. <p> When you do listen to AFSK and you know what a dial-up modem sounds like, it will come as no surprise that they use the same technique to encode digital information. Might have to dig up an old dial-up modem and hook it up to my radio one of these days. <p> Speaking of ancient. The hero of our story, APRS, dates back to the early days of microcomputers. The era of the first two computers in my life, the Apple II and the Commodore VIC-20. Bob WB4APR implemented the first ancestor of APRS on an Apple II in 1982. Then in 1984 he used a VIC-20 to report the position and status of horses in a 160km radius using APRS. <p> As for the International Space Station, the APRS repeater is currently switched off in favour of the cross-band voice repeater, so I'll have to wait a little longer to decode something from space. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The other radios in the world ...
Foundations of Amateur Radio <p> When you join the community of radio amateurs you'll find a passionate group of people who to greater and lesser degree spend their time and energy playing with radios in whatever shape that takes. For some it involves building equipment, for others it means going on a hike and activating a park. Across all walks of life you'll find people who are licensed radio amateurs, each with their own take on what this hobby means. <p> Within that community it's easy to imagine that you're the centre of the world of radio. You know stuff, you do stuff, you invent stuff. As a community we're a place where people dream up weird and wonderful ideas and set about making them happen. <p> Radio amateurs have a long association with emergency services. When I joined the hobby over a decade ago one of the sales pitches made to me was that we're ready to be part of emergency communications. In some jurisdictions that's baked into the license. <p> There was a time when a radio amateur was expected to be ready to jump into a communications gap and render assistance with their station. There are amateur based groups groups like WICEN, the Wireless Institute Civil Emergency Network in Australia, ARES, the Amateur Radio Emergency Service in the United States, RAYNET, the Radio Amateurs' Emergency Network in the United Kingdom, AREDN, the Amateur Radio Emergency Data Network in Germany, DARES, the Dutch Amateur Radio Emergency Service, AREC or Amateur Radio Emergency Communications in New Zealand and EmComms in Trinidad and Tobago to name a few. <p> Each of those manages their participation in different ways. For example, ARES offers training and certification where AREDN offers software and a how-to guide, in Trinidad and Tobago the Office of Disaster Preparedness Management is actively involved in amateur radio and maintains an active amateur radio station and five repeaters. <p> In Australia there's a requirement to record and notify authorities if you become aware of a distress signal as a part of your license. In fact in Australia you must immediately cease all transmissions. You must continue to listen on frequency. You must record full details of the distress message, in writing and if possible recorded by tape recorder. <p> While that scenario can and has happened, it's not common. An amateur station being used to provide an emergency link in the case of catastrophic failure has also happened, but in Australia I'm not sure if that was in my lifetime or not. <p> My point is that the idea that we're going to put up a critical radio link and be the heart of communications in an emergency is, in Australia at least, not particularly likely. That's not to say that you should ignore that potential, or that it's universally true, but it's to point out that there are other things that you can do with your license that might happen more readily and help your community more. <p> Outside our amateur community, there's plenty of radio in use as well. The obvious ones are volunteer bush fire brigades, state emergency services and the like. Less obvious might be the local marine rescue group, surf life saving or the local council. Each of those use radios as part of their service delivery and a radio amateur can contribute to that without needing to bring their station along. In fact, if you don't have an amateur license, but want to play radio, that's an excellent place to do it as a volunteer. I should mention that radio procedures are also in use in all manner of other professions, mining, policing, the military and aviation to name a couple, not to forget occupations like tour-guides, ferry operators and pretty much any place where telephones, fixed or mobile are not readily deployed. <p> Within those areas there are procedures and jargon that you'll need to learn and perhaps even need to be certified for, but you as a radio amateur have several skills that you can bring to the table because you already have a license. <p> For example, I learnt my phonetic alphabet many years before I ever heard of amateur radio. It was a requirement for my aviation radio ticket which in turn was required before I flew solo. When it came to making my first ever transmission on amateur radio, doing the phonetic thing was second nature, much to the surprise of my fellow trainees at the time. A thank you is due to both Neil VK6BDO, now Silent Key, and Doug VK6DB for making that training happen. <p> You can apply the skills you bring with you when you join an organisation outside amateur radio who deals with wireless communication in whatever form that takes. For example, just the idea that you know how to pick up a microphone and push the Push To Talk button and speak and let the button go after you're done, a pretty trivial activity in amateur radio, will be something that you have that most of the untrained general public have no idea about. <p> Amateur radio is a massive hobby. Playing with radio, or doing something serious with it comes in all shapes and sizes. Your amateur experience can help, but be prepared to learn different procedures and methods. The amateur way isn't the only way and it's not the only place where radio is used and sometimes it's good to have a look outside your comfort zone and see what the neighbours are up to. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The impossible task
Foundations of Amateur Radio <p> For decades I've been playing with every new piece of technology that comes my way. In amateur radio terms that's reflected in, among other things, playing with different antennas, radios, modes and software. <p> One of the modes I've played with is slow scan television or SSTV. It's an amateur mode that transmits pictures rather than voice over amateur radio. <p> A couple of months ago a local amateur, Adrian VK6XAM, set-up an SSTV repeater. The way it works is that you tune to the repeater frequency, listen for a while and when the frequency is clear, transmit an image. The repeater will receive your image and re-transmit it. It's an excellent way to test your gear and software, so I played with it and made it all work for me. <p> In 2012 I was part of a public event where local schools participated in a competition to have the opportunity to ask an astronaut on board the International Space Station a question as part of the City of Light 50th anniversary of John Glenn's first orbit. The event was under the auspices of a group called Amateur Radio on the International Space Station or ARISS, an organisation that celebrated its 20th anniversary in 2020. <p> Assisting with the logistics behind the scenes first hand and the amount of equipment used I'd gained a healthy respect for the complexity involved. <p> The ISS has several radio amateurs on orbit. Among their on board activities are plenty of amateur radio friendly ones. In addition to ARISS, you'll also find repeaters, voice, packet and other interesting signals if you listen out for them. <p> In previous years I've made abortive attempts at using my station to listen and transmit to space, with varying degrees of success. <p> On a regular basis the ISS transmits SSTV using amateur radio. Often you'll find a series of images that commemorate an activity. During the final week of 2020 astronauts on the ISS celebrated 20 years of ARISS by transmitting a series of images on a rotating basis as the ISS orbits the earth. <p> One of my friends made a throwaway comment about listening to the international space station and decoding slow scan television. I'd heard about this event on various social media outlets but put it in the too hard basket. <p> Based on what I'd seen during my ARISS event, my own trials, and what local amateurs have been playing with in the way of interesting cross polarised antennas, rotators and the like, I'd decided that this was a long term project, unachievable with my current station. <p> My station consists of a dual-band vertical antenna for 2m and 70cm on my roof at about 2m above ground level. The radio is my trusty Yaesu FT-857d. Connected to a Debian Linux laptop running three bits of software, rigctld, gpredict and qsstv. <p> With a high level of apprehension I fired up my station, tuned my radio, updated the orbital information and radio frequencies and waited for the first acquisition of signal from the ISS. Imagine my surprise when a picture started appearing on my screen. It's a lot like the days of 300 baud dial up, getting a picture from some remote computer back in 1985. <p> With that I managed to receive several of the images by just letting it run for the next couple of days. <p> I'm glad my friend made their comment, because it spurred me into action to try for myself. <p> I'll be the first to admit that the image quality isn't broadcast ready, or that I made mistakes, or that I should have started listening at the beginning of the week rather than the last few days, but all that is just noise because I can report that it works and I have the pictures to prove it! <p> I now have most of the image series, number 2 is missing and I only have part of number 1, but there are some beauties among the 35 images I captured. I've published them on my project website at vk6flab.com, for you to have a look at and use as inspiration for your own seemingly impossible task. <p> This leaves me wondering what else I can hear from overlying spacecraft using this set-up. What have you heard and what equipment were you using to make that happen? Are there any impossible tasks that you've avoided? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Testing a link, on a band, at a time.
Foundations of Amateur Radio <p> The other day I wanted to know what kind of communication was possible between my station and the station of a friend of mine. We want to do some experiments and for that to be possible, we need to have a reliable communication channel. <p> Traditionally you would get in touch with each other and attempt to find a suitable frequency on a band to make a QSO or contact. That generally involves picking a band, then tuning around the band, finding a frequency that's not in use, then listening, asking if the frequency is in use, then telling your friend via an alternative method where you are, only to have them tell you that they have noise at that particular frequency. You go back and forth a couple of times, finally settle in on a mutually convenient frequency and have a contact whilst keeping note of the signal strength shown on your receiver. <p> On a good day that will take a few minutes, on a bad day that might take much longer or not work at all. <p> If you want to do this across multiple bands, you have the fun of doing this whole thing multiple times. <p> In case you're wondering, I've done this plenty of times and I will confess that it's an interesting combination of joy and frustration in attempting to get the answer to a pretty simple and common question: "Can I talk to my friend?" <p> In my shack there are plenty of tools, digital multimeters, LC meter, antenna analyser and the like. No doubt you have some or more of those. Perhaps you have an oscilloscope, a vector network analyser, or other gadgets. <p> None of those are particularly useful tools to solve this particular problem. <p> On the other hand, you are likely to have a receiver and probably a transmitter. If you're reading or listening to this, you're likely to have a computer as well. <p> Using a receiver and a computer as a tool to solve this problem might not have occurred to you. It hadn't occurred to me until recently that these are ideally suited for this particular repetitive task. <p> So, I fired up my copy of WSJT-X and set it to WSPR mode. Changed the band to 2m and set it up to transmit. The other station did the same. Within a couple of minutes the results were coming in. We could both see what the link quality was like between us. Then we changed to 70 cm and did it again. Rinse and repeat for 10m. <p> As it happens, the other station was receive only and they had to attend to some family activities and I was in my office earning a living, well actually, doing my bookkeeping, but you get the idea, you can do this test while you're doing something else. <p> I checked in a couple of times to see how it was going when he pointed out that I could see his actual results on the WSPRnet.org website. <p> I had been looking at the map with mixed results because it had been timing out for most of the day and when it did work, all I could see was that a message was decoded, not how well it was received. Randall VK6WR, the other station, then pointed me at the link to the database which I hadn't seen until then. If you're looking, it's at the top right. <p> Out pops a list of all the WSPR spots his station reported, and as a bonus, the spots reported by another local amateur. <p> If you know me at all it will come as no surprise that I used the opportunity to make a chart. Actually I made several, one showing the frequency drift between our stations, one showing the signal strength. <p> Between the three bands it looks like 2m gives us the best opportunity for experimentation, though 70cm does appear to have some possibilities. Sadly 10m isn't with the antennas currently in the air, but I saw an email the other day with reports of a new vertical at the other end, so we'll have a go at doing the 10m test again in the very near future, perhaps even today. <p> Right now from the WSPRnet.org website I'm downloading this month's WSPR reports from the Downloads section to see who else saw my signals. No doubt I'll make a chart or six. I'll keep you posted. <p> I must thank Randall VK6WR for pointing me at the database link on the WSPRnet.org website, because that made propagation and link testing so much more useful and repeatable. <p> Tools come in all shapes and sizes. What's one that unexpectedly helped you lately? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

When will it ever end?
Foundations of Amateur Radio <p> Mark Twain is often misquoted in relation to reports about his death, pithy as always, he said: "The report of my death was an exaggeration." Similarly the death of amateur radio has been reported on many different occasions. <p> Letting amateurs near a Morse key, banning spark-gap transmitters, introducing transistors, integrated circuits, computers, the internet, software defined radio, the list grows as technology evolves. I can imagine our descendants decrying the death of amateur radio with the commodification of quantum computing at some point in the future of humanity. <p> Yesterday I had an entertaining and instructional play date with a fellow amateur. We discussed countless aspects of our hobby, things like how you'd go about direction finding if you had access to multiple radios and antennas, what characteristics that might have, what you'd need in the way of mathematics, how you'd write software to solve the problem and how you'd go about calibrating such a system. Could you use a local AM broadcast station as a calibration source, or do you need to generate a known signal? <p> We started talking about how you'd send data across the network so you could have a dozen devices in different locations that you could synchronise and share data. How would you control it, how would you make use of existing standards, were there other tools like this already and what were their limitations. <p> Then there was the conversation about using spectrum effectively, seeing current digital modes like FT8 and their level of effective use of a 2.5kHz slice of spectrum with 15 second time-slots and the theoretical bandwidth that you might achieve if you used that mode as a data transmission mode. <p> There was the conversation around how you'd use propagation tools to determine path openings on the higher bands without needing a beacon, just a computer and a radio. <p> Then we talked about how you'd go about making a simple WSPR beacon, based on a minimum component count and some readily available hardware, rather than a sophisticated transceiver like a PlutoSDR. <p> There was a discussion around E-class amplifiers and their characteristics and potential pitfalls. <p> We managed to cover a fair bit of ground in a few hours over our hot beverage of choice, a nice meal for lunch and despite me tripping over the threshold of my front door, banging my head against the wall and rolling my ankle. The head is fine, the ankle not so much. <p> My point is that the world of amateur radio is never done, it's never finished, there's never an end. There's always more to discover, more to explore, build and investigate. <p> How on earth could you contemplate that this was a hobby that had no relevance in the world today, let alone that of tomorrow. <p> I for one am very happy to call myself an amateur and looking forward to discovering what else there is to play with. Why are you an amateur and does this feel like the end or a new beginning every day? <p> The reports of the death of amateur radio was an exaggeration. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

If you want to do HF in an apartment, where do you start?
Foundations of Amateur Radio <p> One of the many vexing issues associated with getting on-air and making noise is actually making that happen. <p> So, let's look at a completely restricted environment. An apartment building, seven stories off the ground, no ability to make holes, an unsympathetic council, restrictive local home owners association, et cetera, et cetera. <p> On the face of it your amateur radio hobby is doomed from the start. <p> In reality, it's only just beginning. <p> So, to hear HF right now, today, you can go online and listen to a plethora of web-based software defined radios. There's the canonical WebSDR in Twente and a whole host of others using the same or similar software. There's KiwiSDR, AirSpy, Global Tuners, and many more. <p> This will give you countless radios to play with, coverage across the globe, the ability to compare signals from different receivers at the same time on the same frequency, the ability to decode digital modes, find propagation, learn about how contests are done, the sky's the limit. I'll add that you don't need an amateur license for many of these resources, so if you're considering becoming part of the community of radio amateurs, this is a great way to dip your toe in the water. Think of it as a short-wave listening experience on steroids. <p> I hear you say, but that's not amateur radio. <p> To that I say, actually, it is. It's everything except a physical antenna at your shack or the ability to transmit. <p> Permit me a digression to the higher bands. If you want to listen to local repeaters on UHF and VHF, listen to DMR and Brandmeister, you'll find plenty of online resources as well. You can often use a hand-held radio to connect to a local repeater which can get you onto the global Echolink, IRLP and AllStar networks. Failing that, there's phone apps to make that connection instead. <p> Of course if you want to expand your repertoire to transmission, beyond a hand-held, you can. <p> There are online transmitters as well. Many clubs have their club station available for amateurs to use remotely using a tool like Remote Hams. You'll get access to a radio that's able to transmit and you'll be able to make contacts, even do digital modes and contests. You will require an amateur license and access to such a station. Some clubs will require that you pay towards the running of such a service and often you'll need to be a member. <p> Then there's actually going to the club, you know, physically, going to the club shack and twiddling physical knobs, though for plenty of clubs that's now also a computer since they're adopting software defined radios just like the rest of the community is. Using a radio via a computer can be achieved directly in the shack, but there's no reason to stay on-site. You can often use these radios from the comfort of your own shack. <p> If you do want to get physical with your own gear, receiving is pretty simple. A radio with a wire attached to it will get you listening to the local environment. I have for example a Raspberry Pi connected to an RTL-SDR dongle that's connected to a wire antenna in my shack. It's listening across the bands 24/7 and reporting on what it hears. <p> If you want to use an actual transceiver and you don't have the ability to set-up an antenna, kit out your car and go mobile. Failing that, make a go-kit with batteries, which as an aside will stand you in good stead during an emergency. Take your go-kit camping, or climbing, or hiking. Plenty of opportunities to get on-air and make noise. <p> I hear you asking, what about having an antenna farm? <p> Well, you can set one up in a farmers paddock and connect to it remotely - you will need permission from the land-owner - there's plenty of amateurs who use their country abode as a remote station. <p> If you want to make noise at your actual shack, the antenna might be a piece of wire hanging from the balcony after dark, or an antenna clamped to the railing. You can use a magnetic loop inside your house. Some enterprising amateurs have tuned up the gutters in their building, or made a flagpole vertical, or laid a coax antenna on the roof. Have a look for stealth antennas, there's a hundred years of amateurs facing the same problem. <p> My own station is very minimalist. There's literally a vertical antenna clamped to the steel patio. Using that I'm working the world with 5 Watts, 14,000 km on 10m, no kidding. <p> Getting on-air and making noise doesn't have to start and finish with a Yagi on a tower. There's plenty of other opportunities to be an active amateur. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

2m reciprocity and other assumptions
Foundations of Amateur Radio <p> Over the past nine and a half years I've been hosting a weekly radio net for new and returning amateurs. Called F-troop, it runs every Saturday morning at 0:00 UTC for an hour. Feel free to join in. The website is at http://ftroop.vk6flab.com. <p> In making the better part of six thousand contacts during that time I've learnt a few things about how nets work and how there are built-in assumptions about how a contact is made. There are several things that seem universally accepted that are not actually supported by the evidence and repeating them to new amateurs is unhelpful. <p> For example, there is an assumption that on 2m there is signal reciprocity. By that I mean, what you hear is what the other party hears. On HF, contrary to popular belief, this is also not universally true due to massive power and antenna differences and signal reports on FT8 bear that out - for example, my signal is often reported at least 9 dB weaker than the other station. <p> The reason that on 2m this isn't the case is because in general there is at least one other transmitter involved, the repeater. If you're joining in via a remote network, either via RF or via the Internet, there are even more times when this isn't true, but let's stay with the simple scenario of a single repeater and two stations. <p> If I'm using a base-station with a fixed antenna, my connection to the repeater is rock-solid. If you are using a hand-held and you're on the move, your connection to the repeater is anyone's guess. It could be great, it could be poor or even non-existent. <p> Not only that, the repeater is often using higher power, sometimes much higher. On average the repeaters near me are using 30 Watts, the highest uses four times that, the lowest uses 10 Watts. In contrast, a handheld uses at most 5 Watts, but more likely than not, half that. <p> Receiving a strong signal on a hand-held is simple, transmitting a weak signal to a repeater is not. <p> The point is, you might be hearing me as-if I'm sitting next to you, but I might be hearing you on the other end of a really scratchy and poor, intermittent and interrupted link. <p> If you add other repeaters and links with differing volume or gain settings to the mix, you get the idea that a 2m conversation may in many ways act like a HF contact. <p> That implies that there are plenty of times when you should use phonetics to spell your callsign and anything else of interest, despite the often repeated assertion that you don't use phonetics on 2m. <p> Another assumption is that 2m is less formal than HF. The people you talk to on 2m are likely to be local, perhaps people you've met at a HAMfest, face-to-face. You recognise their voice, you know their situation, their station and their habits. <p> On HF however, you have contact with people across the globe, most of whom you've never met, will never meet, have no idea about, let alone have a relationship with. That's not to say that you cannot have a friend on HF, I have plenty of people whom I speak with on HF, often during a contest, whom I've never met, but whom I speak with regularly on air. I can similarly recognise their voice, their callsign and know what to expect. <p> The point is that the more you look at the differences between 2m and HF, the more you realise that they are the same. Interestingly, as an aside, a contact on 10m or 15m can on plenty of occasions sound like a strong local FM contact. <p> My advice is to not think of 2m as a "special" band, but to think of it as an amateur band with a set of conditions. By law you are required to announce your callsign every ten minutes and at the beginning and the end of each contact. Note that this doesn't mean at the beginning and end of each over. In case that doesn't make sense to you, a contact is the whole conversation from start to end. Each time a station transmits during that contact is an over. <p> You should vary how you identify yourself, using phonetics or not, at the minimum required interval, or on every over, depending on the circumstances, not depending on the band. <p> Look forward to making contact with you on what ever band. You can get in touch via email, cq@vk6flab.com is my address and if you're into Morse, this podcast is also available as a Morse-code audio file. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Prior Planning Prevents Poor Performance
Foundations of Amateur Radio <p> The other day I was adding an item to my to-do list. The purpose of this list is to keep track of the things in my life that I'm interested in investigating or need to do or get to finish a project. My to-do list is like those of most of my fellow travellers, unending, unrelenting and never completed. As I tick off a completed item, three more get added and the list grows. <p> Given some spare time and to be honest, who has that, I am just as likely to find an item on my to-do list that was put there yesterday as an item that was put there 10 years ago. Seriously, as I migrate from platform to platform, my to-do list comes with me and it still has items on it that haven't been done in a decade, let alone describe what project it was for. <p> Of course I could just delete items older than x, but deciding what x should be is a challenge that I'm not yet willing to attack. <p> Anyway, I was adding an item to the list when I remembered seeing something interesting on the shed wall of a fellow amateur. There were two pieces of printed paper with a list of to-do items on it. Looking pretty much like my to-do list, except for one salient detail. <p> Each to-do list was for a different project. <p> At the time I spotted it I smiled quietly to myself and thought, yep, keeping track is getting harder for everyone. <p> Bubbling away in the back of my mind this notion of a to-do list for a single project kept nagging at me. Yesterday it occurred to me why it was nagging. <p> If you have a to-do list for every project then once the project is done, the to-do list is done. Not only that, the items on a project to-do list don't really grow in the same way as an unconstrained to-do list does. <p> It also has a few other benefits. <p> The sense of satisfaction towards completing a project is amplified as each item is ticked off and ultimately the project is done. <p> I'm sure that project managers already know this, might even have a name and a process for it. No doubt there are aspects that I've not considered, like for example, the never ending range of projects or the trap of a miscellaneous catch-all project, but I'll cross those bridges when I run into them. <p> As of right now, this gives me an improvement on my stifling life to-do list and it brings great satisfaction when I can tick off a whole project. <p> No doubt you've gotten to this point wondering what this has to do with amateur radio? <p> If it hasn't occurred to you, consider what's involved into setting up a portable power supply for when you activate on a field-day, what you need do to get logging working, what needs to happen to get ready for a contest, what you need to do when you're selecting your next radio, how you're going to prepare for the park activation next week and so-on. <p> If you have insights into this, feel free to get in touch. cq@vk6flab.com is my address. Speaking of me, did you know that "Foundations of Amateur Radio" is a weekly podcast and that we're up to episode 285? If you haven't already and you're itching to get your hands on even more content, before episode 1 there was another podcast, "What use is an F-call?" <p> It has 206 episodes and other than the name and my youthful self, the content is more amateur radio. If I've done everything right there won't be much in the way of overlap in those 491 episodes, other than the same unrelenting quest for new and exciting things to do with Amateur Radio, but then you already knew that. <p> Now where's my podcast to-do list? <p> * Tell you about "What use is an F-call?", tick. * Tell you that I'm nearly at 500 episodes, tick. * Finish recording this episode, tick. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

When one WSPR receiver just isn't enough
Foundations of Amateur Radio <p> When one WSPR receiver just isn't enough <p> The other day during a radio play date, highly recommended activity, getting together with friends, playing radio, seeing what you can learn, we were set-up in a park to do some testing. The idea was an extension on something that I've spoken about previously, using WSPR, Weak Signal Propagation Reporter, to test the capabilities of your station. <p> If you're not familiar with WSPR, it's a tool that uses your radio to receive digital signals from WSPR beacons across the radio spectrum. Your station receives a signal, decodes it and then reports what it heard to a central database. The same software can also be used to turn your station into a beacon, but in our case all we wanted was to receive. <p> If you leave the software running for a while you can hear stations across many bands all over the globe. You'll be able to learn what signal levels you can hear, in which direction and determine if there are any directions or bands that you can receive better than any other. <p> We set up this tool in a park using a laptop, a wire antenna and a radio running off a battery. In and of itself this is not particularly remarkable, it's something that has been done on a regular basis all over the globe, and it's something that I've been doing on-and-off for a few years. <p> What made this adventure different is that we were set-up portable about a kilometre up the road from the shack, whilst leaving the main WSPR receiver running with a permanent antenna. <p> This gave us two parallel streams of data from two receivers under our control, using different antennas in slightly different conditions, within the same grid-square, for the purpose of directly comparing the data between the two. <p> Over a couple of hours of data gathering we decoded 186 digital signals, pretty much evenly split between the two receivers. More importantly, the stations we heard were the same stations at the same time which gave us the ability to compare the two decoded signals to each other. <p> One of the aspects of using WSPR is that it decodes the information sent by a beacon. That information contains the transmitter power, the grid locator and the callsign. After the signal is decoded, the software calculates what the signal to noise ratio was of the information and records that, additionally giving you a distance and direction for each beacon for that particular transmission. <p> I created a chart that showed what the difference was between the two, plotted against the direction in which we heard the decode. This means that you can compare which antenna can hear what in which direction in direct comparison against the other. <p> In telling this story another friend pointed out that the same technique could be used to compare a horizontal vs. a vertical antenna, even compare multiple bands at the same time. <p> It looks like I might have to go and get myself a few more RTL-SDR dongles to do some more testing. If you don't have a spare device, there's also the option of comparing other WSPR stations that share a local grid square, so you can see what other people near you can hear and if you like, use it as an opportunity to investigate what antenna system they're using. <p> WSPR is a very interesting tool and putting it to use for more than just listening to a band is something that I'd recommend you consider. I've already created a stand-alone raspberry pi project which you can download from GitHub if you're itching to get started. <p> Thank you to Randall VK6WR for continuing to play and to Colin VK6FITN for expanding on an already excellent idea. If you would like to get in touch, please do, cq@vk6flab.com is my address. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

For that one special event ...
Foundations of Amateur Radio <p> Radio amateurs like to do new things, celebrate, remember, bring attention to, and overall have fun, any excuse to get on air. One of the things that we as a community do is setup our radios in weird and wonderful places, on boats, near light-houses, on top of mountains, in parks, you name it. <p> Another thing we do is create special callsigns to mark an occasion, any occasion. <p> For example, to mark the first time the then Western Australian Chief Scientist, Professor Lyn Beazley was on air she used the callsign VI6PROF. <p> When Wally VK6YS (SK) went on the air to educate the public about Rotary's End Polio Now campaign, he used VI6POLIO. More recently the Australian Rotarians of Amateur Radio operated VK65PFA, Polio Free Africa. When it's active, you'll find VA3FIRE to remind you of Fire Prevention Week in Canada, the Chinese Radio Amateurs Club operates B0CRA through to B9CRA which you can contact during the first week of May each year as part of the Chinese 5.5 Ham Festival. <p> We create callsigns for other things too. <p> Datta VU2DSI commemorates November 30th, the birthday of Indian physicist Sir Jagadish Chandra Bose named by the IEEE as one of the fathers of radio science, by operating a special callsign AU2JCB in his honour for a couple of weeks around the end of November. <p> I mention this because it's not hard to achieve. It's called a "Special Event Callsign" and many if not all amateur licensing authorities have provision for such a callsign. Rules differ from country to country, some say that the callsign must be for something of special significance to the amateur community, others require that it's of national or international significance. In Canada for example, if you're celebrating an anniversary, it must be a minimum of a 25th increment. <p> Different countries have different formats. <p> The USA for example issues temporary one by one calls consisting of a letter followed by a digit followed by a letter. <p> The UK offers GB and a digit followed by two or three letters. There's also "Special" Special Event Stations, which can have a format like GB100RSGB. <p> In Canada there's a whole system based on what kind of event, what region it's significant to, who's operating it, and so on. <p> In the Netherlands you can have a normal prefix followed by at most eight characters and an overall maximum length of twelve characters and you can have it for at most a year and only one at a time. <p> In Germany you can use a standard callsign pattern with a four to seven character suffix, but only for a limited time. <p> In Australia there's the traditional VI and a digit followed by any number of characters, but remember if you make it massive, getting it in the log is not always easy and using a digital mode like FT8 might not work as expected. <p> What ever you want to commemorate, celebrate or bring attention to, remember that your callsign is only one part of the process. Consider who's going to actually operate the callsign, if you're going to issue QSL cards, if there are awards or a contest associated with the callsign, if there needs to be a website, if this is a regular thing, or a once-off. <p> Another thing you need to consider is how you're going to publicise this callsign. There's no point in going to the effort of obtaining a special event callsign with nobody knowing about it, that's the whole point. <p> No matter which way you jump, there's always a large range of special event callsigns on the air at any one time and making contact with one is often a massive thrill for the person operating the callsign, not to mention the person making the contact. <p> So, if you have a chance to have a go, I'd encourage you to get on air with a special event callsign and make some noise! <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

It lives ... crystal radio with three components
Foundations of Amateur Radio <p> The idea of building a crystal radio occurred to me a little while ago. I committed to building one, supplies permitting, before the end of the year. I can report that I now have a crystal radio. It works, as-in, I can hear a local AM broadcast station, and it took a grand total of three components costing a whopping two and a half bucks. <p> Before I get into it, this isn't glorious AM stereo, or even glorious AM mono, this is scratchy, discernible, unfiltered, temperamental radio, but I built it myself, from scratch and it worked first time. <p> Before I start describing what I did and how, I'm letting you know in advance that I'm not going to tell you which specific components to buy, since your electronics store is not likely to have the same components which would make it hard for you to figure out what would be a solid alternative if you didn't understand the how and why of it all. <p> So, disclaimer out of the way, my aim was to build a crystal radio using off the shelf components without needing to steal a razor blade, shave a cat, sharpen a pencil or any number of other weird contraptions. Not that those aren't potentially interesting as life pursuits, though the cats I know might object strongly, I wanted this to be about learning how this thing actually works without distraction. <p> I set about finding a capacitor and an inductor combination that made a resonant circuit with a frequency range that falls within the AM broadcast band. If you recall, you can make a high-pass filter from either a capacitor or an inductor. Similarly, you can make a low-pass filter from either component. If you line up their characteristics just so, you'll end up with a band-pass filter that lets the AM broadcast band pass through. <p> Now notice that I said range. <p> That means that there needs to be something that you can adjust. <p> In our case you can either adjust the inductor, or the capacitor, technically you could do both. My electronics store doesn't have variable inductors, so I opted for a variable capacitor. <p> The challenge becomes, which variable capacitor do you select with which inductor? <p> I used a spreadsheet to show what the bottom and the top range for each capacitor would be if combined with each inductor. This gave me a table showing a couple of combinations that gave me a range of resonance inside the AM band. <p> The formula you're looking for is the resonant frequency for a parallel LC circuit. Take the inductance and multiply that by the capacitance, then take the square root, multiply it by pi and again by two, then take the inverse and you'll have the resonant frequency. You'll need to pay attention to microhenry vs millihenry, and picofarad vs nanofarad and you'll also need to confirm that you've got kHz, MHz or just Hz out the other end, otherwise you'll end up several orders of magnitude in the wrong spot. <p> If you do all that, you'll likely end up with a couple combinations of inductor and capacitor that will do what you want. <p> Then when you head to the electronics store, you'll find that the stock you're looking for is end-of-life and that the colour coding on them isn't right, but if you manage to navigate that swamp, you'll come out the other end with a few parts in your hands. <p> Final bit you'll need is a diode. It acts as a so-called envelope detector. I'm not getting into it here, I'll leave that for another time, but a Schottky or Germanium diode is likely going to give you the best results for this experiment. <p> Wiring this contraption is pretty trivial. Start with joining the inductor and capacitor to each other in parallel, they'll act as the LC circuit. You can change the resonance by tweaking the variable capacitor. Then attach a long antenna wire to one end and an earth wire to the other end. Finally, connect the diode and an amplified loudspeaker in series between the LC antenna end and the LC earth end and your radio is done. <p> For my experiment the loudspeaker has a built-in amplifier, it's an external PC speaker with a power supply. I also had to keep my hand on the antenna to create enough signal - since essentially I'm a large body of water - great for being a surrogate antenna. <p> The unexpected thrill of hearing a local announcer coming through into my shack from three components lying on my desk was worth the anticipation. Highly recommended. <p> What are you waiting for? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The excitement is palpable ...
Foundations of Amateur Radio <p> I'm looking at components. Not looking for, looking at. I have them sitting on the bench in front of me. A collection of six variable capacitors and six inductors. There's also a germanium diode, a breadboard, some connecting wires and two connectors. <p> I don't quite need that many capacitors or inductors and truth be told a breadboard is overkill, but I found myself getting into the spirit of things and for the tiny investment it seems like the thing to get whilst you're dipping your toe into the art of electronic circuit prototyping. <p> I am noticing something odd whilst I'm looking at these components, a familiar feeling in some ways, butterflies in my stomach. It's the exact same feeling as when I sit at the radio, getting ready to speak into the microphone just as I am starting a weekly radio net, something that I've now done about 480 times, not to mention the times when I did around 1600 interviews or broadcast live to the world, butterflies. <p> I'm mentioning this because in many ways this is a momentous event, not for the world, not for humanity, not even for the hobby, but for me. It's the first time I'm building a circuit completely from scratch, no pre-made circuit board, no pre-selected components, no building instructions, just me, some resonance formulas and the hope that I've understood what they represent and that the components I selected will do what my calculations say they should. <p> To make this even less exciting, there's no external power, nothing that's going to go boom or let magic smoke escape, nothing that will break if I get it wrong, but still. <p> The other day I received an email from Phil, WF3W. We have been exchanging email for a couple of years now. He's a member of the Mt Airy VHF Radio Club in Pennsylvania in the United States. <p> His email outlined an interesting question. What do new amateurs get excited about in this era of the ubiquitous world wide web? As a hobby we're attracting new members every day. Many of those are coming to the community by way of social media, rather than using things that are more traditionally considered radio like HF DX, making long distance contact using HF radio, rather than exchanging pithy emails or instant messages via the interconnectedness of the globe encompassing behemoth of the Internet. <p> The answer came easily to me, since last week we had a new amateur, Dave VK6DM who made his very first long distance HF contact between Australia and the United States. His level of excitement was contagious and that's something that I've found happens regularly. <p> Someone talks about magnetic loop antennas and the next thing six amateurs are building them. One person starts playing with satellites and before you know it YAGIs are being built and people are describing their adventures. <p> The same is true with my crystal radio. I've talked about it a couple of times and people are digging out their old kits and telling stories about how they grew up with their dad making a crystal radio. <p> That's what is exciting the new amateurs. The internet is just an excuse to find each other, just like F-troop is an excuse for people to turn on their communications tool of choice at midnight UTC on a Saturday morning to talk about amateur radio for an hour. <p> My excitement comes from trying new things and just like keying a microphone for the first time, there's this almost visceral experience of anticipation associated with starting. <p> I'm still working out how I want to build my new toy and how to go about testing to see if it actually works and what to look for if it doesn't. I'm trying hard to resist tooling up with crazy tools like signal generators and oscilloscopes, instead opting to use things I already have, like LC meters and my ears. <p> I can't wait until I can share how it goes. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Antenna testing in the field.
Foundations of Amateur Radio <p> Antenna testing in the field. <p> If you've been around amateur radio for any time at all, you'll know that we spend an awful lot of time talking about antennas. How they work, where to get them, how to build them, how strong they are, how cheap they are, how effective, how resonant, you name it, we have a discussion about it. <p> It might not be immediately obvious why this is the case. An antenna is an antenna, right? <p> Well ... no. <p> Just like the infinite variety of cars on the road, the unending choice of mobile phones, ways to cook an egg and clothes to wear to avoid getting wet, antennas are designed and built for a specific purpose. I've talked at length about these variations, but in summary we can alter the dimensions to alter characteristics like frequency responsiveness, gain, weight, cost and a myriad of other parameters. <p> If we take a step back and look at two antennas, let's say a vertical and a horizontal dipole, we immediately see that the antennas are physically different, even if they're intended for exactly the same frequency range. Leaving cost and construction aside, how do you compare these two antennas in a meaningful way? <p> In the past I've suggested that you use a coax switch, a device that allows you to switch between two connectors and feed one or the other into your radio. <p> If you do this, you can select first one antenna, then the other and listen to their differences. If the difference is large enough, you'll be able to hear and some of the time it's absolutely obvious how they differ. You might find that a station on the other side of the planet is much stronger on one antenna than on the other, or that the noise level on one is much higher than the other. Based on the one measurement you might come to the conclusion that one antenna is "better" than the other. <p> If you did come to this conclusion, I can almost guarantee that you're wrong. <p> Why can I say this? <p> Because one of the aspects of the better antenna is dependent on something that you cannot control, the ionosphere, and it is changing all the time. <p> I have previously suggested that you listen to your antenna over the length of a day and notice how things change, but that is both time consuming and not very repeatable, nor does it give you anything but a fuzzy warm feeling, rather than an at least passing scientific comparison. <p> A much more effective way is to set up your station, configure it to monitor WSPR, or Weak Signal Propagation Reporter transmissions using one antenna, for say a week, then doing it again with the other antenna. <p> If you do this for long enough you can gather actual meaningful data to determine how your antenna performs during different conditions. You can use that knowledge to make more reliable choices when you're attempting to make contact with a rare station, or when it's 2 o'clock in the morning and you're trying to get another multiplier for the current contest. <p> You don't even have to do anything different and spend little or no money on the testing and data gathering. <p> You can do this with your normal radio and your computer running WSJT-X, or with a single board computer like a raspberry pi and an external DVB-T tuner, a so-called RTL-SDR dongle, or with an all-in-one ready-made piece of hardware that integrates all of this into a single circuit board. <p> If you want to get really fancy, you can even use automatic antenna switching to change antennas multiple times an hour and see in real-time what is going on. <p> You also don't have to wait until you have two antennas to compare. You can do this on a field day when you get together with friends who bring their own contraptions to the party. <p> If there's any doubt in your mind, you can start with a piece of wire sticking out the back of a dongle. I know, I'm looking at one right now. I've been receiving stations across the planet. <p> One thing I can guarantee is that the more you do this, the better you'll get a feel for how the bands change over time and how to go about selecting the right antenna for the job at the time. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The making of a Crystal Radio
Foundations of Amateur Radio <p> Recently I made a commitment to building a crystal radio. That started a fevered discussion with several people who provided many helpful suggestions. This is the first time I'm building a crystal radio and to make things interesting I'm selecting my own components, and circuit diagram. What could possibly go wrong? <p> Crystal radios have been around for a while. Around 1894 Indian physicist Jagadish Chandra Bose was the first to use a crystal as a radio wave detector, using galena detectors to receive microwaves. He patented this in 1901. The advice I was given sometimes feels like it harks back to 1894, with suggestions of using cats whiskers, razor blades, and any number of other techniques that create the various components to make a so-called simple crystal radio. <p> At the other end of the scale there were suggestions to go to the local electronics store and buy a kit. <p> The first suggestions, rebuilding historic radios from parts made of unobtanium would mean many hours of yak shaving, just to get to the point of getting the components, rather than actually building the radio. <p> I realise that part of the experience is the journey and I'm sure that if my current project gets me hooked I'll look into it, but I really don't want to become that amateur who has a collection of home-brew crystal radios across the ages. Besides, I'm having a look at using my crystal radio as a front end to my software, so I want to keep sight of the radio part of what I'm doing, rather than the building part. <p> Before you get all hot and bothered, remember, amateur radio is a hobby that means different things to different people and for me I'm currently playing with software and I'm attempting to learn about the electronics principles that form the basis of our hobby. <p> As I said, the other end of the scale was to get a kit and build that. It has its appeal, but there's little in the way of learning and the construction part of things is pretty much putting together a kit which is something I first did when I constructed an LC meter kit a while ago. So that too doesn't really appeal to me. <p> Now comes the bit where I tell you what I've done to date. <p> On the physical side of things, nothing. On the thinking and learning and planning side, lots. <p> Here's where I'm at. <p> My current understanding of a crystal radio is that you need to detect the AM wave form of an RF frequency and pipe that into something that makes noise. Traditionally this is done with a crystal earpiece, but I saw someone use powered computer speakers with a built in amplifier, so I'm going to start with that as my first noise maker. <p> I should also mention that the crystal earpiece was a source of confusion. I thought that the crystal in crystal radio was referring to that one. It's not. <p> So, back to where I'm at. What do I need? <p> To start off, I cannot just connect an antenna to a speaker, since it will attempt to make sound for every known frequency, well, at least the ones that the antenna can handle that fit within the response envelope of the speaker and its amplifier. If you want to know what that sounds like, put your finger on the input plug to some powered speakers. Don't turn up the volume too loud, you'll regret it. <p> So step one is to make a way to only let specific frequencies through. I've previously discussed this. You might know it as a band-pass filter. You can make one using a capacitor and an inductor. If you make the capacitor variable, you can change what frequency passes. This is helpful because you don't want to be decoding more than one radio station at a time. <p> There are plenty of designs for crystal radios that offer hand wound inductors and home brew capacitors, but I'm not doing this to learn how to build those, I'm doing this because I want to learn how it works. I want to use readily available components from my local electronics store, so I started with building a spreadsheet that shows what the resonant frequency is for a combination of inductors and variable capacitors. <p> Today I learnt that I also need to pay attention to how wide this is, so I'll be revisiting this. <p> There are only two more components in my radio, a diode and another capacitor. The diode cuts off half of the information, since if you recall, AM uses two side-bands that are identical. At that point you have a signal that contains both the carrier and the audio signal. You need one last step, filter out the high frequency carrier. I've talked about that too, this is a low-pass filter. You can do this with a capacitor. <p> So, now we have the bare-bones of a crystal radio, made from four components, an inductor, a variable capacitor, a diode and another capacitor. My next challenge is to figure out what values they have so it will allow me to listen to my local AM radio station and do it using components off the shelf from my electronics store. <p> One thing I can tell you is that this is precisely why I signed up for this project. I don't want a ready-made radio from a kit and I don't want to have to learn how to chop down a tree in order to make a pencil. <p> I'll keep you posted. If you have additional reading material you'd like to suggest, feel free to get in touch. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

An ionospheric monitoring service at home
Foundations of Amateur Radio <p> One of the more fundamental aspects of long distance radio communication is the impact of the ionosphere. Depending on how excited the Sun is, what time of day it is and what frequency you're using at the time will determine if the signal you're trying to hear from the other side of the planet makes it to you or is on its way to a radio amateur on Proxima B who is likely to hear this podcast in just over 4 years from now. <p> In other words, the ionosphere can act like a mirror to radio waves, or it can be all but invisible. <p> As luck would have it, this changes all the time. Much like waiting for the local weather bureau for the forecast for tomorrow's field-day, there are several services that provide ionospheric predictions. The Australian Space Weather Service, SWS, is one of those. You might have previously known it as the Ionospheric Prediction Service, but Space is much more buzz-word compliant, so SWS is the go. <p> If you're not a radio amateur, space weather can impact stuff here on Earth, like the ability to communicate, transfer energy across the electricity grid, use navigation systems and other life-essentials. The SWS offers alerts for aviation and several other non-amateur services. <p> If you're interested in HF communications, the SWS offers HF prediction tools that allow you to check what frequencies to use to communicate with particular locations using visualisations like the Hourly Area Prediction map. <p> If you're more of the Do-It-Yourself kind of person, you might be pleasantly surprised that you can have your very own ionospheric monitoring station at home. Not only that, it's probably already in place, configured and ready to go. <p> If you're using WSJT-X to monitor WSPR transmissions, then you'll have noticed that the screen shows all the stations you've been able to decode and you can scroll back as far as you like to the time when you launched WSJT-X. <p> If you want to do some analysis on that, copy and paste is an option, but it turns out that there's a handy little document being stored on your computer called ALL_WSPR.TXT that contains the very same data going back to when you installed and launched the first time. <p> This information represents what stations you heard, at what time and with what level of signal to noise at your shack, not some fancy station in the middle of nowhere with specialist hardware, your actual station, the one you use to talk to your friends, with your antenna, your power supply, the whole thing. <p> For my own entertainment I've been working on a way to visualise this. I created a map that shows the location every station I've logged, 30,000 of these reports in the past four months. It's interesting to see that I can hear most of the globe from my shack. Notably absent is South America but that is likely a combination of band selection and local noise. <p> In the meantime I've gone down another rabbit hole in figuring out if I can use an image file to visualise all this without needing fancy software, unless you consider a web-browser and bash fancy. <p> The idea being that a simple script could take the output from your station and convert that into a map you can see on your browser. In case you're wondering, I'm thinking that a style-sheet attached to a Scalable Vector Graphic or SVG might be just the ticket to showing just how many times I've heard a particular grid-square. <p> If you have ideas on what else you might do with this data, get in touch. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

csdr will rock your world ...
Foundations of Amateur Radio <p> When you start playing with software defined radio, you're likely to begin your journey using something with a display that shows you a lovely waterfall, gives you a way to pick out a frequency, decode it and play it over your speakers all over the house. Likely your first effort involves a local FM radio station. These graphical tools come in many and varied forms available on pretty much anything with a display. Tools like SDR#, cuSDR, fldigi and WSJT-X. <p> That can be immensely satisfying as an experience. <p> Underneath the graphics is software that is essentially translating an antenna voltage to a sound, in much the same way as that happens in an analogue radio. There are the parts that get the signal, then they get translated and filtered, translated some more, decoded, and eventually you have sound coming from your speakers. <p> During the week I caught up with a fellow amateur who pointed me at the work of Andras HA7ILM who for a number of years has been quietly beavering away making various tools in the SDR landscape. <p> One of those tools has the innocuous name of "csdr", a command-line software defined radio digital signal processor. It started life on November 1st, 2014 and has had many updates and community changes since. <p> This tool has no graphics, no user interface, nothing visible that you can toggle with a mouse and yet it's one of the coolest tools I've seen in a long time and from a learning perspective, it's everything you might hope for and then some. <p> Before I explain how it works, I need to tell you about pipes. They're much like water pipes in your home, but in computing they're a tool that allow you to connect two programs together so you can exchange data between them. <p> One of the ways that you can think of a computer is a tool that transforms one type of information into another. This transformation can be trivial, like say adding up numbers, or it can be complex, like filtering out unwanted information. <p> The idea is that you take a stream of data and use a pipe to send it to a program that transforms it in some way, then use another pipe into another program and so on, until the original stream of numbers has become what you need them to be, creating a transformation pipeline with a string of programs that sequentially each do a little thing to the data. <p> That stream of data could be numbers that represent the voltage of the signal at your antenna and the final output could be sound coming from your speaker. <p> If you were to take that example, you could use one tool that knows how to measure voltage, pipe that to a tool that knows how to convert that into FM and pipe that to a tool that knows how to play audio on your speaker. <p> Converting something to FM is, in and of itself, a series of steps. It involves taking the raw numbers, extracting the part of the samples that are the station you want to hear, decoding those and converting that into something that is ready to be played on your speakers. <p> This process is fundamentally different from using a so-called monolithic tool that does everything behind the scenes. The person writing the software has decided what to do, how to do it, in what order and in what way. If you want to do something that the author hadn't thought of, like say listening to a new type of broadcast, you'll be waiting until they update the software. <p> In another way, this is the difference between making a cake from raw ingredients and buying it up the road at the shops <p> One final part of the puzzle. <p> There's nothing preventing you from piping the output of your program to another copy of the same program. <p> So, if you had a tool that knows how to do the maths behind filters, AM and FM decoding, translating Lower Side Band into Upper Side Band and vice-versa, band filtering, etc., you'd be able to set up individual steps that translate a signal, one step at a time, from raw antenna data into a sound you can hear. You would have all the building blocks for the fancy tools that you are used to. <p> csdr is such a tool. <p> For example, it knows how to set the gain of a signal, how to up and down sample, how to shift frequencies, how to decode them, it knows about RTTY, PSK, AM, FM and do about a hundred other things. <p> So far I've mentioned decoding, but there's nothing stopping you from starting with plain text, piping that into csdr and converting that to a PSK31 audio signal and transmitting that audio on your radio. <p> To make it even better, because it's so modular, you can look at the math behind what's going on and begin to understand what's happening behind the scenes. <p> Of all the tools I've found in the past decade, I have to confess, this is the one that has stopped me in my tracks. <p> Thank you to Randall VK6WR for introducing me to this tool and to Andras HA7ILM for writing it. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

New day, new mode ... SSTV
Foundations of Amateur Radio <p> In 1958 The Kentucky Engineer published an award winning student article by Copthorne "Coppie" MacDonald. He described a Slow-Scan T.V. System for Image Transmission. If you get the opportunity, have a look for the link on his archived home-page which you can find from the Wikipedia SSTV page. <p> The purpose of this narrow band television idea was to be able to send images using cheaper equipment and less bandwidth than normal television. The idea caught on and it's still in use today. <p> In 1959 the idea of slow scan tv was used by the Luna 3 mission to transmit images from the far side of the moon. The NASA Apollo program also used SSTV to transmit images from Apollo 7, 8, 9 and from the Apollo 11 Lunar Module. <p> In 1968 SSTV became a legal mode for radio amateurs in the United States. <p> The International Space Station regularly uses SSTV to send images to radio amateurs across the globe. <p> The version of SSTV in use by radio amateurs today is different from the earlier grainy black and white images coming from the moon and if you're expecting a moving image, something that TV implies, you're going to be disappointed, since the popular SSTV modes send images one at a time, taking up to a minute or so to send. With a frame-rate of one frame per minute, watching anything other than grass grow is going to be a challenge. <p> That said, SSTV is a lovely and relatively simple way of sending images across the air. <p> In my quest for new adventures I like to play with things I know nothing about. I suspect that it's ingrained but it does keep me off the street. The other day I received an email from a local amateur, Adrian VK6XAM, who sent a message describing a new SSTV repeater he'd set-up for testing purposes. It's a local 2m repeater that waits for an activation tone, then it expects you to transmit an SSTV image and it will replay the image back to you. If you've familiar with a parrot repeater, this is a similar thing, just for SSTV rather than audio. The repeater is running on solar power and with the 100% duty cycle of SSTV, it's only available during daylight hours. <p> Technicalities aside, I couldn't resist. <p> So, I fired up QSSTV, a piece of Linux software that among other things knows how to receive and send SSTV images. After turning on my radio, tuning to the correct frequency, I received my first ever SSTV picture. <p> On a bright red background a yellow symbol appeared. At first I thought it was a hammer and sickle, but on closer inspection it was a micrometer and caliper, which absolutely tickled my fancy, having just taken delivery of some precision measuring tools - a Mitutoyo Test Indicator and a few other bits and pieces for another project I'm working on. <p> Had to learn how to drive QSSTV, make a template so you can overlay text on an image, learn what a signal report should look like, then when I figured all that out I triumphantly hit send and it made all the right noises, but nothing was happening. <p> More time looking at the inter-web taught me that if I want to use the rear connection on my FT-857d to send audio using FM, as opposed to SSB which is what most digital modes need, you need to set the radio to PSK mode and magically it starts to work. <p> My first ever SSTV image was sent an hour and a half after receiving my first image and the repeater dutifully sent it back. Then I got a picture from Keith VK6WK. <p> Of course the paint isn't even dry on any of this, so there's plenty more to learn, but the process is not too complex. <p> I will note a few things. <p> I had already set-up digital modes, that is, my radio was talking to my computer via CAT, that's Computer Assisted Tuning, essentially a serial connection that controls the radio and the audio was already being sent and received from the rear connector of my radio. <p> Getting SSTV running was really an extension on those activities, so if you're going to do this, take some time to make things work. I continue to recommend that you start with WSJT-X since it helps you get your levels and connections right. <p> Now I suppose I should start playing with SSTV over HF, but first I would like to figure out how to make the templates work better for me and how to actually seriously log an actual contact. <p> More adventures ahead! <p> Remember, have fun, play, get on air and make noise! <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Simplicity among the complexity ...
Foundations of Amateur Radio <p> My radio shack consists of two radios, identical, well, in as much as that they're the same model, a Yaesu FT-857d. Their memories are different, their microphones are different, but both of them are connected via a coaxial switch to the same VHF and UHF antenna. One of them is also connected to a HF antenna. <p> Let's call these two radios alpha and bravo. <p> Alpha is used to host F-troop and play on the local repeater. Bravo is used to do HF stuff. It's also connected to a computer via a serial cable, called a CAT cable, Computer Assisted Tuning, but really, a way to control the radio remotely. <p> The audio output on the rear of the radio is also connected to the computer. <p> These two connections are combined to provide me with access to digital modes like PSK31, WSPR and SSTV, though I haven't actually yet made that work. The computer itself is running Linux and depending on what I'm doing on the radio some or other software, often it's fldigi, a cross-platform tool that knows about many different digital modes. <p> The computer is also connected to the Internet via Wi-Fi, and is used to see what various reporting websites have to say about my station, things like propagation, the DX cluster, an electronic way of seeing what other stations can hear, then there's solar radiation information and other neat tools. <p> This shack is pretty typical in my circle of friends. I'm lucky enough to have a dedicated table with my shack on it, for others they're lucky to have a shelf in a cupboard, or at the other end of the spectrum, a whole room or building dedicated to the task. <p> The level of complexity associated with this set-up is not extreme, let's call it in the middle of the range of things you can add to the system to add complexity. <p> In case you're wondering, you might consider automatic antenna switching, band switches, band filters, amplifiers, more radios, audio switching, automatic voice keyers. If you look at the world of Software Defined Radio, the hardware might include many of those things and then add a computer that's actually doing all the signal processing, making life even more complex. <p> At the other end of the complexity scale there's a crystal radio. <p> As I've been growing into this field of amateur radio it's becoming increasingly clear that we as a community, by enlarge, are heading towards maximum complexity. <p> There's nothing wrong with that as such, but as a QRP, or low-power operator, I often set-up my radio in a temporary setting like a car or a camp site. Complexity in the field is not to be sneezed at and I've lost count of the number of times where complexity has caused me to go off-air. <p> It occurred to me that it would be helpful to investigate a little bit more just what's possible at the other end of the scale, at the simple end of complexity if you like. <p> So, I'm intending, before the year is out, supplies permitting, to build a crystal radio from scratch. I realise that I have absolutely no idea what I'm getting myself into, no doubt there will be more complexity that I'm anticipating, but I'm getting myself ready to build something to be able to look at it and say to myself, look, this is how simple you can get with radio. <p> I'm currently too chicken to commit to making the simplest - legal - transmitter, but if you have suggestions, I'll look into it. <p> Just so you know, simplicity is an option. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Yak Shaving ...
Foundations of Amateur Radio <p> Yak Shaving ... <p> Not every adventure gives you an outcome. Today started with reading a thank-you email from a listener who shared their activities and wanted to express their gratitude for encouraging them to get on air and make noise. <p> That in turn prompted the question on the country of origin of that listener and did I know where all my listeners were? For the past few hours I've been attempting to answer that seemingly simple question. <p> Aside from using the opportunity to make an attempt at mapping the distribution of amateurs in Australia, which on the face of it is a trivial exercise, consisting of extracting the postcode from each registered amateur and then putting those on a map. <p> Only the postcodes are not actually single points. They're boundaries defined by Australia Post and they're copyrighted. Not only that, they change. To access them, you have to pay the Post Office. If you want to combine a postcode with a population density, so you can see where amateurs are represented and at what level, you go to the Australian Bureau of Statistics for a population density data-set. At that point you realise that the Bureau uses standardised regions. Mesh-blocks at the smallest end of the scale are essentially the size of 30 to 60 households. The Bureau uses these as the fundamental size for all its statistics. <p> When you attempt to map this onto postcodes you learn that there isn't a one-to-one mapping and even if there was, it would change every time Australia Post changed a postcode boundary. <p> I will note that this is all by way of a side-street in my investigation. I wondered how amateur radio is distributed across the country and I didn't want to end up with essentially a population density map, more people means more amateurs, I wanted to see where amateur radio had the potential to affect more people because there are more of them in a group. <p> Anyway, then I attempted to look at the podcast downloads and map those to countries. I use AWS CloudFront to make the podcast available, so it gets to the user, you, quicker. The logs show which data-centre a request is handled by. Then I needed to map a data-centre to an airport code, look that up in a database so I could extract the country, then count how many requests were made per country. <p> Then I started doing that across time, so you can see how that changes over time. <p> At this point I still don't actually have a map to show. <p> While all this was happening, my computer started running low on disk-space, not because I'd just downloaded some data from the Australian Bureau of Statistics, but because some rogue process was writing a log somewhere, so I spent an hour looking for what process that was, killing it and removing the superfluous log file. <p> If this sounds familiar, there's a name for it. Yak shaving. It's originally named after a Ren and Stimpy episode called "Yak Shaving Day". Essentially you do a whole lot of unrelated activities in the pursuit of the actual activity, essentially a string of dependencies that distract you from the end-goal. In my case, trying to answer which countries are represented within my audience. <p> Why am I not using an amateur radio example? <p> Two reasons. <p> This is amateur radio. For me. Doing charts, wrangling data, massaging stats, finding answers and presenting those are an integral part of the hobby, to me. Just like making this podcast, contributing to discussion, reading and learning. All part of the mix. <p> Second reason is that I wanted to illustrate this with something that wasn't immediately obviously linked to the hobby for most people. A more amateur example might be wanting to go and operate portable, attempting to locate you battery, when you find that it's not charged, so you go looking for the charger which you find has a broken connector, so you drive to the electronics store to get the connector when you run out of petrol, so you pull over, get out of the car and trip over the curb and end up in hospital emergency waiting for a doctor to see you. If you think that's far-fetched, I know an amateur who ended up in hospital from yak-shaving. <p> We've all had days like that. <p> The idea is that any day that you are on the right side of the earth, doing something you love is a good day. <p> Regardless of the end result, this is a hobby after all. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What is so different about using software for signal processing?
Foundations of Amateur Radio <p> In my ongoing software explorations I've discussed that Software Defined Radio or SDR is a fundamentally different way of dealing with radio. It's been in use across non-amateur circles for decades. Your mobile phone has an SDR on board for example. <p> The original term of "digital receiver" was coined in 1970, "software radio" was coined in 1984 and in 1991 Joe Mitola reinvented the term "software radio" for a planned mobile phone base station. <p> So, this idea has been around for half a century and in amateur radio this idea is also catching on. You can buy a few pure SDR devices today, some hybrid ones, or you can begin to experiment in a more indirect manner using your traditional radio and a computer. <p> One of the things that sets this idea of a software defined radio apart from anything we've done so far is that the bulk of the signal processing is done in software. That sounds obvious, but it's really not. <p> One of the impacts of this idea is that you can improve your radio communications by either writing better software, or by using a faster computer. Unless you write software for a living, these things aren't immediately obvious, so let me explain. <p> Imagine that you've written software that detects beeps in a particular slice of audio spectrum that's being fed to your application. As you write better software to detect those beeps, you get a better digital mode, one with a better chance of being decoded, or using radio terms, it has a better signal to noise ratio. <p> If that's not a familiar term, signal to noise ratio is the a measure that describes the difference between a wanted signal and the background noise. Higher signal to noise means that you can better distinguish between the two. <p> If you stand in a room full of people talking and you use your hands to cup your ears towards the person you want to hear, you've increased the signal to noise ratio and your chance of understanding them has improved. <p> As you write this software, it gains complexity. As you deal with more maths, more samples, more tests, you end up running out of time to make your decoder return a relevant answer. There's no point in having a real-time signal being decoded late. If it were to take say 10 seconds to decode 1 second of audio, then the next second would be 20 seconds late and the one after that would be 30 seconds late. <p> That's where a faster computer comes in. <p> If you have the ability to do more maths, or do the same maths at a higher resolution, you will essentially improve the reception of your radio without ever needing to change your antenna or anything on the circuit board. <p> Think of it in another way. <p> Imagine that your tool has access to 2.3 kHz of audio. It's the equivalent of a Single Side Band audio stream. If you break that down into 23 chunks of 100 Hz each, you can deal with the average of 100 Hz of audio for each calculation. If you have a faster computer, you might be able to break that down into 230 chunks of 10 Hz each, or 2300 chunks of 1 Hz. So instead of doing calculations across 23 chunks of audio, you're doing it across 2300 chunks. <p> Why is this significant you might ask? <p> Well, in a traditional radio you get one bite at the cookie. You get to design and build your circuit and then package it and sell it. The end result is something like my FT-857d. It does what it does well, but it will never get any better. <p> However, if I plug that same radio into my computer, I can extract the audio and do stuff with it. If I get a faster computer, I can do more stuff. I don't have to change my radio, or my antenna, or even my shack. Most of the time I run a different application and I get a different result. <p> I will point out that I'm deliberately ignoring where and how the RF gets to the computer, or where that computer actually is, or what operating system it's running, since none of those things matter to get an understanding of how changing software can change the performance of your radio. <p> I've said this before and I'll say it again: "The SDR earthquake will change our hobby forever" <p> Before I go. I'm not for a minute suggesting that your current radio is obsolete. If it were legal, a spark-gap transmitter could still exchange information today, but if you want to explore what might be just over the horizon, going down the SDR path by connecting your radio to your computer is a really nice place to start. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

When you run into a pounce ...
Foundations of Amateur Radio <p> Contesting is a fun way to learn about amateur radio. It tests your skill, your station, your patience and your ability to change approach at a moments notice. For those reasons alone it's an activity that I recommend you have a go at. <p> For me it's also about self-improvement. With each contest, can you make better use of your station, can you learn more about your radio, about bands, about conditions and ultimately become a better operator. I know that there are individuals who keep telling me that giving out signal reports of 5 and 9 isn't helpful, to them I say, try it in a contest setting and see what else you learn. <p> When you start out contesting you'll quickly come across two terms, technically three, that need some explanation. The terms are Run, Search and Pounce, though the last two come as a matched pair. <p> The essential bit of information is that when you're on a Run, or Running, you're calling CQ and responding to other stations. You essentially sit on a frequency for a bit, start calling CQ and hope that others hear you and start to gather around to make contact with you. <p> The other side of that is Search and Pounce, or searching on a band for a station you want to talk to and pouncing into a gap when you can. <p> The two methods are mirror images of each other, so one station is generally running whilst the stations calling in are searching and pouncing. <p> Doing this in a contest setting requires slightly, some might say subtle, differences. <p> Let's investigate a contest RTTY contact. I'll simulate it between myself, VK6FLAB and Matt, VK6QS. I'll add that this is done in text in a RTTY contest, rather than voice, and, this exact exchange didn't actually happen, but for different reasons which I'll get into shortly. <p> It goes a little like this. <p> My station transmits: CQ TEST VK6FLAB VK6FLAB CQ Matt responds: VK6QS VK6QS VK6QS I reply: VK6QS 599 010 010 Matt replies: 599 032 032 And I finish off with: TU CQ VK6FLAB <p> Now this is the ideal contact, nothing extraneous, no duplication, nothing about having to repeat yourself. Mind you, if you're getting picky, you might notice that we're both sending our exchange twice, in my case 010, Matt is sending 032. <p> If you look closer you'll notice that all pertinent information is sent at least twice because it turns out that unlike a keyboard on a computer connected to a screen, what you type in RTTY might not actually get to the other end if you're using HF radio. <p> My three transmissions are the one where I call CQ, the one where I say Matt's callsign plus the exchange and the one where I say TU or Thank You, and move on. Those are the run calls. <p> Matt's calls consist of his callsign, and his exchange. <p> Note that Matt doesn't say my callsign, since I already know it and I'm running and he's searching and pouncing. He should already know who I am before he transmits. If he were to add my callsign, that would just slow things down. This is a way to keep things moving along. <p> In fldigi, I can program a function key that does each of those five calls. You click on a callsign, push the appropriate button and magically you're either running or pouncing. There's also a button for asking for a repeat, or "AGN?, AGN?" and one for making a log entry, which you can combine into the final thank you for running, but it's needed separately if you're pouncing. <p> I did say that this exchange didn't actually happen and you might well wonder why I shared it with you. <p> Simple. This is the bare-bones of what's required. Everything else is extra in case things break down. If there are multiple stations on the same frequency, or if your levels aren't quite right and the decoder is having a hissy fit, the human in the chain, you, need to do something manually. Very much like when you're dealing with a voice pile-up and there's this one station calling over the top of everyone else and drowning out whomever you actually want to talk to. <p> In a contest setting there's plenty of opportunity to do both running and pouncing and you should. If you're running on a dead band you won't know because you're getting old calling CQ, but if you're searching on that same band you'll figure out pretty quick that there's nothing happening. <p> Similarly, you might have a desirable callsign or location and find that running is more effective in making contacts than searching and pouncing. <p> Whatever mode of contesting you choose, make sure that you're flexible, since band conditions change from second to second and you will need to adapt to the winds of change. A lot like when you learn to sail and find out that you cannot just hold the helm in one spot for the entire time. <p> I will note that the ideal RTTY contact that I've outlined isn't universal. There's plenty of debate about the most effective way to go about things. I started with what I knew about making voice contacts, shamelessly copied the RTTY macros from another amateur and used them as a basis to learn what I needed and what I didn't, and because this was my first actual RTTY contest I watched several YouTube videos, rather than hear actual contesting stations on the air, which is something I recommend you do to get a feel for what's going on. <p> Contesting can be a way of life, or it can be just plain fun with learning thrown in. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

After channelling your RTTY ...
Foundations of Amateur Radio <p> It's the morning after the day before. I've been calling CQ for 24 hours and for the first time in my life after a contest I still have my voice. That in and of itself is novel. I also don't have ringing ears, that's a blessing. I have learnt heaps and had fun doing it. I made contacts and I heard stations across the globe and I did it all from the comfort of my shack chair. <p> Before I dig in and expand, the contest I just completed ran for 24 hours. I didn't sit at my radio for all of it, nor was my radio on for all of it. I managed to have lunch, dinner, desert, breakfast and morning tea. I snuck in a few naps and I managed to help with bringing in the shopping. My station did not transmit unattended at any time in case you're wondering. <p> My setup consisted of a little 11 year old netbook computer running the current version of Debian Linux and the heart of this adventure, the software called fldigi. The computer is connected to my Yaesu FT-857d via three cables, well, two and a half. A microphone and a headphone lead that combine into the data port in the back of the radio. The other cable is a USB CAT cable, a Computer Assisted Tuning cable, that plugs into the CAT port on the back of the radio. I also used an external monitor to have my main contest screen on and used it to display the main fldigi window. <p> My license class allows me access to a selected number of amateur bands, 80m, 40m, 15m, 10m, 2m and 70cm. I managed at least one RTTY contact on each band. <p> As I described previously, my radio is set to use Single Side Band and the audio from the radio is fed via the microphone socket on the computer into fldigi that processes the information. Similarly, when I transmit, the audio is generated via fldigi and leaves the computer via the headphone socket and goes into the radio as a Single Side Band audio signal. <p> The information in the audio is all RTTY, a digital mode that I've described previously. The software is using Audio Frequency Shift Keying, AFSK, simulating the switching between the two RTTY frequencies. <p> On my screen I have a waterfall display that shows all the signals that are happening within the 2.3 kHz audio stream that's coming from the radio. Fldigi is also decoding this in real-time and showing each decode as a virtual channel in a list. Click on a channel entry and your next transmission will happen at that frequency. <p> If you've ever used WSJT-X this will sound very familiar. <p> That's the mechanics of what I've been doing. <p> So, what did I learn in this adventure? <p> Well, most of Australia goes to sleep at night, at least the ones that do RTTY. I have evidence of exactly one station on-air, and that was only because they were named in the DX Cluster, which by the way this contest allows as assistance. Since then I've found logs from at least two more stations. <p> Local contacts did happen during the more civil hours and in total I managed ten of them. You may think that's not much for say 12 hours of work, but that's 5 Watts QRP, or low power, RTTY contacts, in an actual contest, on a new antenna, from my shack, dodging thunderstorms and learning to use filters and levels. <p> You might not be impressed, but I'm absolutely stoked! <p> During the midnight-to-dawn run, on 40m, when there were double points to be had, which I missed out on, I did manage to hear several stations across Europe, 14,000 km away, which means that I can pretty much count on global coverage with my current setup. Sadly they didn't hear me, too many competing stations, but I'm sure that with practice I'll manage to contact them too. <p> The software crashed once. That's not nice. It seems to have a habit of corrupting one of the preference files, which prevents it from starting up. That's also not nice. I hasten to add that I don't yet know the source of this. It may well be a dud-hard-disk sector on my ancient laptop, rather than the software, so I'm not assigning blame here. <p> Getting started with fldigi is an adventure. It's not point-and-click, nor plug-and-play, more like running a mainframe whilst cranking the handle, but when you get it to fly there's lots to love about this tool. <p> Other things that worked well were that I'd spent some preparation time getting the keyboard macros right. These are pre-defined bits of text that you send as you're calling CQ and making a contact. They're a whole topic in and of themselves, so I'll skip past the detail and just mention that I was very happy with the choices I made, gathered from years of voice-only contacts, reading RTTY contest information and looking for exchange details. <p> From a technical perspective, I used both contest modes, "Running" and "Search and Pounce". Running is when you call CQ, Pouncing is when they call CQ. The running was by far the most successful for me. I'm not yet sure if that was a reflection on how much I still have to learn about levels. <p> One thing that I can say with confidence is that there's absolutely nothing like having a wall of RTTY signals to learn how to make sure you're actually decoding something useful. I spent a good couple of the wee hours tuning my levels. <p> I would like to thank the stations who came back to my call and for those who tried without me noticing them. <p> I had a blast. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Channelling RTTY
Foundations of Amateur Radio <p> When you start playing with radio your first interaction is likely to be voice. It could be SSB, AM, FM or something more recent like FreeDV or DMR. Your next challenge is likely going to be a digital mode like Morse Code, Radio Teletype or my recommendation for your first adventure, WSPR or Weak Signal Propagation Reporter. <p> I've previously discussed WSPR, today I would like to look at Radio Teletype or RTTY. It's a digital mode that allows you to send and receive free-form text. It's a mode with a long and illustrious history and it's a good next step after WSPR. <p> The way it works is that using an alphabet made up from two tones, information is transmitted, one character at a time at a specific speed. The code that describes the alphabet is called the Baudot code, invented by Jean-Maurice-Emile Baudot in 1849. In computing terms it's a 5-bit alphabet and in amateur radio it's traditionally sent at 45.45 baud or bits per second, in case you're wondering, named after the very same man. <p> The two tones have names, a Mark and a Space and they're a set distance apart. In amateur radio, they're separated by 170 Hz but there are plenty of other frequencies and speeds in use. In amateur radio the standard Mark and Space frequencies are 2125 Hz and 2295 Hz. <p> In a traditional RTTY capable radio the two tones are generated by transmitting a carrier whilst switching the transmitter frequency back and forth, called Frequency Shift Keying or FSK. Think of it as having a Morse key that sends dits on one frequency and dahs on another, having the radio change frequency whilst you're keying. <p> If you use this method to create and decode RTTY by switching between two frequencies, your radio can generally only deal with one RTTY signal at a time, just the one you're sending and just the one that's being received. Receiving is generally achieved by showing some indication on your radio how close you are to the Mark and Space frequencies that you're trying to receive and decode. <p> Another way to make a RTTY signal is to use sound. If you alternately whistle at 2125 Hz and 2295 Hz and you do it at 45.45 bits per second, you're also generating RTTY. This technique is called Audio Frequency Shift Keying or AFSK. Think of it as using audio to simulate the shifting of frequency by transmitting two alternating tones. <p> There is a fundamental difference between the two. Before I explain, permit a diversion. It's relevant, I promise. <p> If you've ever spoken on the radio using SSB you might have noticed that if two stations are transmitting at the same time you get both signals. With a little practice you can even understand both. This isn't true for every radio mode. If you use FM, the strongest signal wins and if you use AM, you get a garbled beep from two stations being on slightly different frequencies. As an aside, this is why aviation uses AM, so any station not transmitting can hear that two stations doubled up. <p> Back to RTTY. <p> If you use audio to generate the two RTTY carriers, rather than shift frequency, you can deal with as many as you can fit into an SSB audio signal, as long as the Mark and Space for each station are 170 Hz apart you can have as many stations as you want, overlapping even. As long as your software knows what to do with that, you'll be able to decode each one at the same time, since they're essentially multiple SSB signals being transmitted simultaneously. <p> An added bonus is that you don't have to invest in an SDR to play with this. You can use an analogue radio, like my FT-857d, and use software to generate an audio RTTY signal with all the benefits I've just mentioned. The magic is in the software you use to do the decoding. <p> As it happens, I'm about to do a contest using RTTY and I'll let you know how that goes using my radio, a computer and a piece of software called fldigi. I'll be following in the footsteps of the first ever RTTY contest, held in the last weekend of October in 1953 and organised by the RTTY Society of Southern California. In as much as I'm following in the footsteps of Morse code by spark-gap. <p> Wish me luck. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How much do you really know about your radio?
Foundations of Amateur Radio <p> When I came across amateur radio nearly a decade ago I did a course, passed my test and got licensed. At that point I didn't have any equipment, didn't know about any, hadn't touched anything, other than the radio in the classroom, and had no idea about what to buy and how to choose. <p> So, instead I asked the friend who introduced me to the hobby, Meg, at the time VK6LUX, what radio to get. I asked her what was the second radio she ever got because I figured that I'd get very disappointed with the first one in short order. She explained that there were plenty of brands to choose from and that each had their own champions. Just like the perennial choice between Ford and Chevrolet, Apple vs Microsoft, Tea vs Coffee, you'd end up with one radio and be told by someone in a different camp that you chose the wrong one. <p> Her advice, which is just as solid today as it was a decade ago, was to buy something that people you knew had, so whilst you're learning there'd be someone nearby who could help. As a result I bought a Yaesu FT-857d for precisely that reason. I still have it and it has a sister, another FT-857d, bought when I needed to broadcast the local news when one of the local volunteers went on holiday. <p> For most beginners their journey is similar. They buy their first radio and generally that sets the tone for what comes next. <p> In the decade that I've been around amateur radio I've had the opportunity to play with about 30 or so different radios. For some that playing consisted of picking up the microphone and making a QSO, a contact, and not much else. For others it consisted of sitting with the radio for a full contest, 48 hours, with sporadic sleep, dealing with pile-ups where there wasn't time to breathe, but plenty of stuff to learn about filtering. <p> Then there were the radios that came to my shack for a visit, those at various clubs and plenty of outings where I was able to sit down and figure out how stuff works. <p> On the surface that's all fine and dandy. A radio is a radio, you pick up the microphone and hit go, off to the races. Then you need to figure out how to set the volume, change frequency, change bands, read what the mode is and how to change it, tune the thing, set up a filter, change the pre-amp, operate split. <p> For some radios this was easy, consisting of a channel button and a microphone push to talk, for others there were no buttons, just a big Ethernet socket, then there were the radios with a hundred buttons, some so small that you missed them on first glance. I've used solid-state radios, valve radios, software defined radios and virtual radios, each with their quirks and idiosyncrasies. <p> Every time I operate a new radio I learn something about that radio, but I also learn something about my own radio. I can begin to hear differences, observe how easy or hard it is to do something, a missing feature on my own radio, or the one I happen to be operating at the time. <p> In my travels I've seen plenty of radio amateurs who only have a passing understanding of their own radio, let alone any other radio. <p> I completely respect that this might be enough for you, but I'd like to point out that this might be a missed opportunity. <p> I remember vividly sitting in the middle of a bush-camp with my own radio powered by a battery connected to a hap-hazard dipole antenna strung between two trees attempting to hear a station discussing her global circumnavigation by sailing boat and being frustrated with my ability to make it work. <p> A friend who was sitting nearby asked if they could have a go and within seconds he was able to use the filters and offsets to make the station pop out of the noise. It's with the image of Kim VK6TQ in mind, the person who knew my radio better than I did, that I'd like to urge you to play with any radio you come across, no matter how trivial or different. <p> One day it will mean the difference between making a contact or not. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

First Digital DX contact!
Foundations of Amateur Radio <p> The other day day I managed my first DX contact using a new mode, FT8. It wasn't very far away, all of 2600 km or so, but it evoked memories of my first ever on-air DX contact nearly a decade ago. I should say thank you to YD3YOG for my 15m contact, fitting because my first ever was also on 15m as I recall. Unfortunately I never did log my first. <p> Recently a friend asked me how the two compared. <p> 15m and logging aside, there's a lot of similarities, even though I'm a more experienced operator today when compared to when I made my first ever contact. <p> The preparation and the building anticipation is what made the contact all the sweeter. <p> A while ago I managed to connect the audio of my radio to a computer. This is pretty much the first step in starting to use digital modes. Essentially many common digital modes use an SSB transmission to generate and receive audio that in turn contains digitally encoded information. <p> There are hundreds of modes like this, from PSK31 to RTTY, WSPR, FT8, SSTV and many more. If you've not yet dabbled in this area, I'd recommend starting with WSJT-X. The software is so far the best tool I've found to make sure that your digital levels are correct and offers several popular modes to see how your station is operating. If you're asking for a first mode recommendation, I'd start with WSPR. Just do the receive part first, then work on from there. <p> There are many tutorials available, some better than others, so if the one you find doesn't float your boat, keep looking. A fly-over view is that there are several things that you need to get working and if they don't all work together, you'll get no result. <p> Obviously you'll need to install the software, but that's not the whole story. For the software to be able to control your radio, change bands, frequency and set-up things like split operation, you'll need to set-up the hardware to do this, in my case a CAT cable between the radio and the computer. You'll also need to set-up control software that knows how to talk to the hardware. In my case that's Hamlib on Linux, but it could be Hamlib or flrig on MacOS or something like OmniRig on your Windows machine. <p> The purpose is to control the radio. When you're troubleshooting, keep that in mind, hardware plus software need to work together to control the radio and this is before you actually do anything useful with the radio. <p> Then you need to have both hardware and software to have audio go between the computer and the radio. In my case the headphone and microphone connectors on my computer are connected to the data port on the back of the radio. If your computer doesn't have access to sockets you might need to use a USB sound-card. If your radio doesn't have an easily accessible port, you might need to have an interface. <p> The computer software in this case is likely setting the volume levels using the audio mixer in your operating system. <p> I will add that some radios have a USB socket on the back that combines both CAT control and audio. The principle though is the same. You need to make the CAT interface work, which is essentially a serial connection, and you need to make the audio work, which is essentially a sound-card. <p> Nothing else will make sense until you've managed to make those two work. <p> Then, and only then, can you try to launch something like WSJT-X, point it at the various things you've configured, then you can actually start decoding signals. <p> For WSJT-X to work properly, there's one more thing. An accurate clock is required. Likely you'll need to use a piece of software that knows how to synchronise with something called NTP or Network Time Protocol. The simplest is to point your clock tool at a time-server called pool.ntp.org which will get you global time coverage. Each operating system does this differently, but getting it right is essential before WSJT-X will actually make sense. You can visit time.is in a web browser to see how accurate your clock currently is. <p> So, get computer control of your radio working, get audio working, set the clock, then you can run WSPR, FT8, JT65 or any other mode. <p> I will note that I'm not attempting to give you specific computer support here, just an overview of what's needed before anything will work. <p> If you've been contesting then CAT control might already be operational. If you've been using a computer voice-keyer, then audio might also be ready. Depending on where you are on your digital journey, these steps might be complicated or trivial. <p> Once you've done all that you can start doing things like figuring out where satellites are or how to talk to the International Space Station, or use Fldigi to make a PSK31 contact or send a picture using SSTV or decode a weather fax. <p> When you've made that first digital DX contact, I'm sure that you too will have a sense of accomplishment! <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What do you talk about?
Foundations of Amateur Radio <p> When was the last time you told anyone anything about your hobby? What about someone who isn't also an amateur? <p> Have you ever considered why there is a perception that our hobby is dying, why it's running out of people, why we struggle to get air-time in mainstream media, why attracting new members is hard and why there is a very narrow range of understanding about what our hobby is, what it does and how it's relevant in the world today? <p> I'm a radio amateur. So are you. You might not be licensed yet, but the fact that you're here right now indicates a willingness to understand and learn, to participate and question. <p> Those qualities are the fundamental building blocks that make up a radio amateur. <p> I'm also a self-employed computer consultant, a radio broadcaster, an interviewer, a software developer, a public speaker, a blogger, author, publisher and a partner. My friends include people who are process managers, astronomers, gynaecologists, mariners, tow truck drivers, communications technicians, volunteer fire-fighters, business owners, employees, retirees, fathers, mothers, old, young and everything in between. Radio Amateurs one and all. <p> When you sign up to be an amateur, you don't give up all the other things you are. You don't stop being a member of society, you just add in another box marked radio amateur and you get on with your life. <p> If you get into this hobby you begin to realise that it sneaks into everyday life all the time. You use it to figure out how something works, or explain why it doesn't, you use it to trace a circuit or to plug in your new surround sound system. You use it to encourage curiosity in your children and to talk to your grand-children. It's not an add-on, it's part of who you are. <p> That's always been the case, but the perception in the general public has not been like that, it's been based around the idea that being a radio amateur is being special, being separate, being knowledgeable, studied, licensed. The reality is that the world we live in is more connected than ever and the things we once did in isolation are now part of mainstream life. <p> There is a perception that amateur radio is dying. Articles describe how we need to attract more people, how we need to appeal to children, how we need to recruit, become sexy or relevant. There's discussion about what's broken in the hobby, how we need to fix it. <p> I think that none of those things are what's in need of investigation. I think it's us. You and I. I think we need to stop being shy about being a radio amateur, about what we do and why we enjoy it; what it means and how it works. <p> When you talk about your activities of the day, if you made a rare contact with Tuvalu, or managed to connect your computer to your radio, or made an antenna work, or climbed on a hill or learnt Morse Code, you need to share your victories and the excitement that they bring you. <p> As a society we're not shy about tweeting what we had for breakfast, sharing an interesting picture or discussing an article we saw on reddit. Fundamentally what you do and who you are is worth talking about and sharing. <p> So, next time you talk about going camping, or discuss a barbecue you had with friends, or relate to your friends something that happened, don't be shy about your amateur radio affiliation. <p> It's not a secret society, it's not weird or embarrassing, it's just part of what makes you who you are. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What's the point of this hobby?
Foundations of Amateur Radio <p> One of the recurring questions in this hobby, technically outside this hobby, asked by people who've not yet, or have only just been bitten by the bug, is: "What's the point of this hobby?" <p> In some ways I too have asked this question, though for me the answer came within a few months of learning that amateur radio exists. In response to others asking this I've also made meagre attempts to answer this question with varying degrees of success and satisfaction. <p> The typical responses are things like: there's a thousand hobbies inside amateur radio, it's about the communication, about the camaraderie, about climbing and hiking, about technology, science, physics, electronics. The truth is that this is just a fly-over view of what it means to have this as your hobby. <p> It occurs to me, having now been licensed for a little while, I can actually express a little more clearly what this hobby has given me. <p> At a basic level, I now know what the front of a TV aerial is and how Wi-Fi is attenuated by walls, how line of sight works and why you can talk to the International Space Station with a hand-held radio. I've learnt about sunrise and sunset and how they affect propagation, the grey line and how the ionosphere is broken into layers that are affected by solar radiation. I've learnt about sunspots and how they change over time, that there are cycles, that there is a thing called the Maunder Minimum and that propagation is a fickle beast. I've learnt about the Ionospheric Prediction Service and about band planning in contests, about dealing with pile-ups and making contacts, about voice-keyers and computer controlled radios, about contesting software and logging, about contest scoring and contest rules. <p> I've learnt about gain and about loss, about how 75 Ohm coax differs from 50 Ohm coax, how connectors work, about soldering and crimping, how to use a crimper and what connectors to use with which coax. I've learnt about path-loss and about bouncing signals off the moon, about Sagittarius A*, a bright and very compact astronomical radio source at the centre of the Milky Way and about inclination and ascension, about galactic coordinates and observation windows, about programming in Python and the astropy library. <p> I've learnt about how radio signals are used to encode information, the seemingly infinite supply of digital modes and how a radio signal can be described in three dimensions. I've learnt how maths can describe amplitude modulation and how side-bands can be described, about signal to noise ratios and decibels. <p> I've experienced the joys of making a rare contact, to places like Amsterdam Island, Prince Edward & Marion Island, Heard Island, Micronesia, Cuba, Kiribati, and many more. I've learnt more about geography, about maidenhead locators, learnt new phrases and started learning new languages. <p> I've gone out camping more times than I can count, spent nights under the stars making contacts across the globe. I've set-up my station in parks and on peaks across the country, made life-long friends locally and abroad, tested my patience and my endurance. <p> I've learnt about the pioneers and inventors who came before me, about their successes and failures, their enduring legacies and their inventiveness. I've gained insight into Apollo radio communications and distance measuring, global positioning before there was GPS, about satellite dishes and radio during disasters, about emergency communications and temporary set-ups with just enough to get the job done. <p> I've written software, made charts, learnt how to use GNUPlot, written articles, recorded podcasts, interviewed amateurs, published books, produced, presented and transmitted amateur news broadcasts, built amateur radio websites, chaired meetings, raised funds, contributed to club committees and helped as I was able. <p> I've helped organise a national amateur radio conference, learnt how to teach others and created a weekly radio net for new and returning amateurs. I've acted as a point of contact, offered life advice and acted as a shoulder to cry on when the going got tough for some of my fellow amateurs. <p> I've built more, tested more, explored more, learnt more and done more in the past decade than I have in the 40 years before that. <p> When I look back over the 472 podcast episodes I've written so-far, that massive list is only just scratching the surface and it only just begins to describe how deeply affected I've been by this hobby. It only barely describes the width and depth of this hobby and I've only been here for a little while. <p> I must point out that I did all these things because I could, because I had radio amateur friends who prodded and poked, who helped and asked, who gave and received. My exposure over this decade was only possible because there are others who share my interests and stopped to take a moment to express that. <p> Next time you're asked about how amateur radio is relevant, how it relates to the world, how it affects you and your life, what it's given you, or what you can gain from it, consider, even just for a moment, just how much is possible within this massive hobby. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Homebrew radio for the 21st Century
Foundations of Amateur Radio <p> The hobby of Amateur Radio is essentially one of experimentation. Within our community we endlessly build things, from amplifiers to Yagis and every letter of the alphabet in between. With every experiment we grow the amateur radio sphere of influence just a little bit. <p> As our hobby is evolving into Software Defined Radio, or SDR, the homebrew aspect of our community is also changing bit by bit and as a result, homebrew today is just as likely to be based on software as it is in hardware. <p> Unlike the physical world where you need to source and buy components, design a circuit, build it, test it and then put it in a box, in the software realm you can get started with the computer that is more than likely within reach right now. <p> Recently I took delivery of a new SDR, an ADALM Pluto. It's essentially a Linux computer, FPGA and transmit capable SDR in a small box. I bought it specifically for the purpose of experimentation. <p> One of the first things I did with this device was install an existing piece of software called dump1090. The tool listens to 1090 MHz and decodes Mode S transponders, used by aviation to report aircraft information in real-time. <p> Originally written by Salvatore Sanfilippo in 2012 for the RTL-SDR dongle, it was patched by several people and in 2017 it was updated by Jiang Wei to support the Pluto SDR. My contribution to the project is minor. I've updated the on-board web-server to use Open Street Map and a few other cosmetic changes. <p> For me it was a "Hello World" project, something that's the software equivalent of warming up your soldering iron and pre-tinning the wire you're about to use. <p> The tools to do this is what I want to discuss. <p> When you look at the software that underlies much of the SDR world, the digital modes, logging, contesting, even the software inside tools like the Nano-VNA, much of it is open source. That means that as a curious amateur you can have access to the underlying equivalent of the circuit diagram. As you can with a soldering iron, a scribe and wire, you can patch or update a circuit. In the software realm you can do the same once you have access to the source code. <p> The tools you're going to get in touch with are text editors, compilers, libraries and configuration files. If that's not your thing, I appreciate that, but if it sparks your interest, you'll open the door into a brand new world of software development where you can determine how a mode works or what it supports or how it interacts with your radio or testing gear. <p> When you jump in, likely feet first, you're going to make mistakes and lose hair and sleep and you'll be shaking your virtual or physical fist at the person who came before you, but then that's the world of experimentation, so likely you'll already have that down pat. <p> You'll likely play with different tools that require different versions, often installed side-by-side, much to your chagrin when you learn that it just won't work. Not to mention that removal of the offending tool often leaves interfering cruft behind, not unlike unsightly and short-circuiting blobs of solder. <p> I'm here to introduce you, albeit briefly, to a tool that will take much of that pain away. The free tool is called Docker. It has got little in the way of visibility in the amateur radio world, but in the software development world it's pretty much old hat. <p> Essentially the idea is that you can install stuff into a so called disposable container so you can have your copy of dump1090 installed in one container and your copy of codec2 in another, a copy of rtl-sdr in a third container, all working independently from each other, without needing to complicate things with multiple computers or virtual machines. If a developer uses Debian, another uses Ubuntu and a third uses Red Hat, you can run these side-by-side without any issue. If they need an ancient version of something, that too is handled without a problem. Make a mistake, destroy the container and start again, fresh. <p> Docker is a tool that allows you to build an environment on Linux, MacOS and Windows, as well as the Raspberry Pi, that acts and behaves in many ways like a virtual machine. In all the ways that you're likely to use it, at least initially, it's indistinguishable. What that means is that the operating system, the compiler and the libraries that you need for one tool won't affect those needed for another tool. <p> The best part of this is that you can build on a massive library of pre-existing Docker containers and use files that describe how to build and compile tools like dump1090. <p> If you look for my callsign vk6flab on github.com, you'll find my version of dump1090 and you'll find a Dockerfile that describes how I built it. The project contains all the bits you'll need to get started with your own version of dump1090, or some other project that tickles your fancy. <p> Every time you build something, the amateur radio sphere of influence grows just that little bit. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What is a repeater offset and how does it work?
Foundations of Amateur Radio <p> Every week I run a net for new and returning amateurs. A variety of people join in with varying degrees of skill, knowledge and number of birthdays. <p> One of the regular things I say during that net is that if I'm not acknowledging you, it's because I cannot hear you. I then start a spiel about repeater offsets and give some examples, but what is it really and how does it work? <p> As you might recall, a repeater is a radio, generally located somewhere useful, like on a hill or tall building, that offers the ability to talk to other amateurs who are not within range of your radio. <p> For bands like 2m, 70cm and 23cm, generally speaking, contacts are line-of-sight. If you're standing on a hill, you can talk to more people because your line of sight is further away. <p> This is also why you can talk to the International Space Station with a hand-held, since it's in your line-of-sight, at least some of the time. <p> A repeater acts as a line-of-sight extender. If it can see both you and another station, it can act as a bridge between you. <p> How it does this is pretty simple. A repeater listens to your signal and transmits that to the other station. It uses two separate frequencies to make this happen. A receive and a transmit frequency, or more precisely an input and an output frequency. To remember which is which, you can think of a repeater as a giant megaphone, you talk into it and sound comes out. Said differently, think of a repeater as a device that takes an input from one station and makes an output for everyone to listen to. <p> To actually use a repeater, your radio needs to be setup to transmit on the repeater input and it needs to receive on the repeater output. This means that when you transmit, the repeater can hear you and when you're listening, you can hear the repeater. <p> To achieve this, you can set your radio up using repeater mode. It uses a thing called an offset to set the difference between the input and output frequencies. <p> To find out what the offset is, you take the repeater input frequency and subtract the repeater output. If you've set-up your radio correctly you're tuned and listening to the repeater output. When you hit the Push to Talk or PTT, you'll transmit on the input frequency and when you let go, you're back to receiving on the output frequency. <p> One final roadblock might be that your local repeater has a tone lock. If it does, the repeater will ignore you even if you have all the frequencies correct. This tone is generally published by the repeater owner or your local regulator. You can also check a website called repeaterbook.com to see many of the world's repeaters and their specific settings. <p> Now, I should point out that while repeater offsets are standardised, they're not the same across bands, across the world, or even within a country or city. Depending on where you are, what the density of repeaters is and what band you're on, the offset number and direction will change. <p> It's even possible that you have a variety of offsets on the same band in the same city. This means that you cannot just pick a standard offset for your radio but most modern radios will have a method to deal with this. <p> It's easy to get this wrong. <p> Setting up your radio for using a repeater is deciptively simple. Three things to look out for when it's not working. You have the input and output reversed, the offset is wrong, or there's a tone blocking your transmission. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Your antenna is a filter (of sorts).
Foundations of Amateur Radio <p> The single most discussed topic in amateur radio is that of antenna design, that and medical procedures on 80m, but I kid. Previously I've discussed the notion that all frequencies are on-air all the time and that your traditional radio uses much of its electronic circuitry to filter out all the things you don't want to hear. <p> Parallel to that is the concept that you tune your antenna to be resonant on a particular band or frequency. As amateurs we might look for a wide-band antenna that makes it possible to use our radio across several bands. We often construct our antennas to be multiple harmonics of a band so we can have access to more spectrum without needing more physical antennas. <p> None of this is new and as an amateur you'll likely spend the rest of your days improving your antenna situation, or at least talking about it, if not outright bemoaning the lack of antenna space, family approval, budget or some other excuse. <p> As I started my journey into Software Defined Radio a new idea occurred to me. If an antenna is a resonant circuit, could you think of your antenna as a filter, as-in, something that leaves out the things you don't care about? <p> In and of itself I'm sure I'm not the first to consider this notion, but the idea means that you essentially turn your idea of an antenna on its head, from something that receives to something that rejects. <p> Consider for example the small transmitting loop antenna, often also called a magnetic loop antenna. It's got one characteristic that isn't often considered a benefit, it has something called a High-Q, or a high Quality Factor. The higher the Q, the narrower the bandwidth. <p> I should digress here for a moment. Q is a number. Big number means narrow bandwidth, little number means wide bandwidth. It's easy to calculate. If you look at an SWR plot of an antenna you'll see a curve where the bottom of the curve is the lowest SWR of your antenna, that's the centre frequency. You'll also see two points on the same curve where the SWR hits 2:1. If you take the centre frequency and divide that by the difference between the two edge frequencies, you'll have the Q of that antenna. <p> Using numbers, consider an antenna that's got an SWR below 2 between say 7 MHz and 7.2 MHz, a bandwidth of 200 kHz, you'd have a centre frequency of 7.1 MHz. The Q of that antenna would be 7100 divided by 200 or a Q of 35.5 <p> If you had an antenna that had a bandwidth of 5 kHz at 7.1 MHz, it would have a Q of 1420. <p> And just to wrap that up. This is helpful because just comparing bandwidth on different antennas doesn't tell you enough. Is an antenna that has 400 kHz bandwidth on 20m more or less selective than an antenna with 200 kHz bandwidth on 40m, what about 100 kHz on 80m? <p> Back to the small transmitting loop antenna or mag-loop. If you're using such an antenna on an amateur band like say the 40m band, you'll likely have to re-tune your antenna every time you even think about changing frequency. I've had the frustration of using a manual version of such an antenna and it can wear thin very quickly. <p> I'm bringing this up because it can also be a benefit. <p> Imagine that you need to make a contact on a busy band during a contest. Often you'll find yourself setting up the filters on your radio, trying hard to remove all the extraneous noise that comes from strong signals nearby. <p> What if your antenna could help with that? <p> What if you thought of your antenna as a pre-filter, something that makes the job of extracting just that signal from the bit of spectrum you're interested in? <p> My point is this. <p> We're talking about an antenna that from one perspective can be a pain to use, requiring constant retuning, constant adjustment, just to get on the air and make noise. <p> From another perspective, that very same antenna is a way to filter out the things you don't want to hear and extract the signal you care about. <p> How you approach this depends on your perspective and just considering your antenna as a filter might help you see another side of your antenna system that you hadn't considered before. <p> How you use this is entirely up to you. For my money, I'll be doing more experiments. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

If you WSPR and nobody hears you ...
Foundations of Amateur Radio <p> The day came to pass when all my set-up and configuration was going to culminate in the moment of truth when I enabled TX on my WSPR mode station. Before I tell you of my experience, I should give you a little bit of background. <p> A few weeks ago I managed to erect a HF vertical at my home or QTH. That in and of itself was news worthy, well at least to me it was, since it was the first time since I became licensed in 2010 that I had actual real all-band HF capability at home. Last weekend I ran some RG6, yes, 72 Ohm Quad Shield, low-loss coaxial cable, from my antenna, through the roof, into my shack. <p> I was thrilled. <p> Immediately set about getting my HF station up and running. This involved installing WSJT-X, a tool that allows you to do weak signal work, perfect for when you're a low power or QRP station like me. I've previously reported using WSPR, Weak Signal Propagation Reporter on a Raspberry Pi and a dongle, but this time I was using my Yaesu FT-857d. <p> Reports were coming in thick and fast. Managed to hear stations on all the bands I'm allowed on, 80m, 40m, 15m, 10m, 2m and 70cm. Managed to make it report online and update the various maps around the place. <p> Brilliant! <p> Now I wanted to do the next thing. Transmit and see who could hear me and how far my beautiful callsign might travel on 5 Watts. <p> So, after some abortive attempts, I configured the levels correctly, made sure that my antenna coupler, an SG-237, was tuned and hit "Enable TX" on the screen of my computer. <p> Dutifully my computer did what was expected, turned on the transmitter and happily made the fan run on my radio for two minutes at a time. I tried 80m, 40m and 15m. All worked swimmingly. <p> Then I looked on the map to see who had heard me. <p> Nobody. Nothing. Nada. Niets en niemand. <p> I could hear N8VIM using 5 Watts, 18649 km away, but nobody could hear me, not even the station VK6CQ who is 9 km from me. <p> So, what's going on? <p> Turns out that I'm not using a "standard" callsign. That's right, my VK6FLAB, authorised by the World Radiocommunication Conference 2003, implemented by the Australian regulator, the ACMA in 2005 and issued to me in 2010 isn't a standard callsign. <p> Seems that the deal-breaker is the four letter suffix, FLAB, that's killing my attempts at making contact. <p> Now I know that there are moves under way, not quite sure what stage they're at, to allow Australian amateurs to apply for any three-letter suffix and keep that regardless of their license level, but that to me doesn't really solve the underlying issue, where a perfectly legal callsign isn't allowed to be used by one of the most popular modes today. <p> I've lodged a bug report on the WSJT-X mailing list, but to accommodate this callsign will probably require a fundamental change in the way the WSPR mode and likely several other JT modes will work, not to mention the databases, the maps, API calls and other fun things like logging. <p> Technically I could have figured this out back in September 2019 when I was first allowed to use digital modes with my license, but I didn't have an antenna then. <p> In case you're wondering. I also investigated using a so-called extended, or type-2 message, but that allows for an add-on prefix that can be up to three alphanumeric characters or an add-on suffix that can be a single letter or one or two digits. <p> I could use something like VK6FLA/B, but I'm sure that the owner of VK6FLA would be upset and using VK6/F0LAB might have a French amateur yell Merde! at me when they spot their callsign being transmitted from VK6. <p> One suggestion was to upgrade my license. <p> What's the fun in that? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Using something for an unexpected purpose can give you many great rewards.
Foundations of Amateur Radio <p> The other day I was getting ready to go out when rain started pelting down. Not unexpected in this part of the world at this time of year but inconvenient for my plans. <p> I didn't particularly want to carry an umbrella and the thought of wearing a rain hood brought back memories of water trickling down my back. <p> For reasons I'm not quite sure of, my eye fell on my hat on its hook at the door. The hat I wear in the heat of summer to keep my brain from frying, the hat I use whilst camping with my amateur radio friends, the hat I've worn whilst loading massive hay bales with a tractor and the hat I've worn swimming in the Ord River - well, a descendent, third generation if I remember correctly. I shook my head in disbelief, after donning my raincoat, put my trusty Akubra Territory on my head and stepped out into the rain. Perfect. Kept me dry, kept my glasses clear and no drips down my back. <p> You may well wonder what this has to do with radio and that's a fair question. I will preface this with a disclaimer that you might not have this set-up in your shack just now, but perhaps it will inspire you to get started. <p> I've been talking a lot about Software Defined Radio, and I do believe that it represents the future for our hobby, but that doesn't mean that my traditional radio, in my case a Yaesu FT-857d, is headed for the scrap heap just yet. <p> As you might know, with some preparation you can connect your radio to a computer and control it. You can also connect both the send and receive audio to a computer using a variety of techniques which I probably should get into at some point. <p> Assuming that you have, and I realise you might not yet have done this, but assuming for a moment that you have made this all work, you can use this to do things like JT65, FT8, PSK31, SSTV and hundreds of other modes. <p> One thing I did during the week was use this set-up to listen to noise. Seriously, that's what I did. I picked a spot on the band with nothing but noise. No discernible signal and fired up the application WSJT-X, it's the tool you use for many weak signal modes. As an aside, as a tool, it is also helpful in getting your digital mode levels set correctly. <p> One of the windows in WSJT-X is the waterfall and spectrum display. On it you can see the signal as it is right now and how it's been in the past. <p> If you turn on one of the filters on your radio, you can see the display change. You can literally see what gets filtered out. On my radio I've got the standard filter, as well as a 2 kHz and a 300 Hz Collins filter. Using this technique, you can specifically see what each filter does. If I turn on the built-in Digital Signal Processor, the DSP, I can see what the adjustments do, as well as the impact of the mode on the filter. And how the various settings interact. <p> For example, until I saw this display, I didn't know what the "DSP HPF CUTOFF" and "DSP LPF CUTOFF" specifically did and how they interacted with the other filters. Similarly what "DSP BPF WIDTH" did and how. <p> I also didn't know that even if you set both the high and low pass filter frequencies to the same value, you still have a usable filter, even if you might think that nothing could get through. <p> Now I do realise that your radio may not have those specific settings, but I am confident that if you pick a spot on the band, set up a frequency display and waterfall, you'll discover things about your radio that you hadn't before. I also realise that you can hear some of this by just playing with filters, but seeing it on the scope adds a whole other dimension to the experience. Just one example is to see how a narrow filter interacts with the in-built DSP, something that's difficult to hear, but easy to see. <p> If you have a Morse beacon to hand, you can also see how various frequency shifts work and the impact of selecting filters in relation to that signal. No need to just listen to the beacon with just CW mode either. Have a look at it using SSB. <p> Using something for an unexpected purpose can give you many great rewards. As for the hat, really, I hadn't used my hat to ward off the rain until then; you live and learn. <p> What have you discovered recently? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How to pick a field operating position?
Foundations of Amateur Radio <p> Much of the operation that I've done as a radio amateur is conducted in the field. That is, I tend to either drive my car to a location, or go out with friends and set-up camp to play. After you do this for a while you start to notice the things that you look for in an operating position. <p> The very first one is accessibility. That is, how easy is it to get there? It's fine coming up with the ultimate location, but if it's an hour's drive away and you've only got an hour to play, you'll spend all your time getting there and you'll be home late. <p> By contrast, for field days lasting several nights, I've regularly driven more than a hundred kilometres to find the spot, sometime much more than that. The point is that the accessibility changes depending on your available time. The journey to the location can be just as much fun as the destination itself. <p> How long you plan to be there will determine what antennas you might want to set-up. If you're there for an hour, you'll likely use a vertical on your car. If you're there for the weekend, your antenna farm will be determined by how much wire you brought and what you can hang it off. <p> Hanging antennas is the next thing. You can bring your own poles, but for height, nothing beats a solid tree. The taller the better. More taller, more better. If you have several to choose from, you get to play with all manner of fun stuff. For one antenna contraption we had three trees that we ran a wire between. They were roughly spaced in a triangle about 200 meters apart from each other. As I recall, the antenna we built, a massive V-beam managed to talk to Europe for most of the weekend. <p> For another adventure a simple G5RV dipole was hoisted high into the trees. Another was accomplished by strapping a pole to a fence and setting up an inverted-V antenna. Recently we set-up an antenna that was nothing more than a wire running over the ground. <p> So, generally speaking height is good. You can cheat by having a low tree and a hill. Or a fence and a pole, or a gazebo and tent-pegs. What ever you can do to attach an antenna to will work to some degree. Which reminds me, if your hill is tall enough, it's likely to have a communications tower on it for someone, if not everyone. They're not the end of the world, but they can cause havoc with noise. Depends entirely on what the communication structure is used for. Bear in mind, some of these sites have noisy solar panel inverters or generators, so that too needs to be taken into consideration. <p> Another factor in picking a location involves water. Setting up a vertical on a jetty is gold. I've made many long-distance contacts using a vertical with a ground wire running into the ocean. Note that you don't have to actually get wet. Being near the ocean is often enough. I've had plenty of success from a beach car-park from a vertical on my car. <p> In general, man-made objects such as houses, factories, other cars, power lines, generators, boats, camping grounds with solar panels and plenty more are often bad news for HF communications. The biggest disappointment happens when you take the time to go to a site, set up camp, build your antennas, turn on the radio and all you hear is the noise from a nearby source of interference. <p> That said, you don't need to travel to the ends of the earth either. 15 minutes from my house is a lake with a park. There's a car park which on occasion attracts a motor home with a solar panel, but by enlarge it's a local park with people going for a walk. From a radio perspective, despite homes, businesses, schools and cars nearby, the place is heaven. It's quiet, it has shade, running water, fence posts and I regularly make contacts from there, right in the middle of the city. <p> That brings me to another aspect. Creature comforts. <p> Setting up near a busy road isn't fun. Neither is sitting in your car without shade. Having amenities within reasonable distance helps. For example, recently for a field day we set-up within 10 minutes drive from a regional centre. Didn't even notice it was there, happily dropped in for shopping and a meal. Some beers might have been consumed. <p> That same site also had high voltage power lines near our location. The only difference was that our site was above the power lines at the top of a hill, so we never even noticed them. <p> Finally, some of this is all about picking a camp-site that's suitable for radio, rather than a radio site that will handle camping. You get better at it the more you do it. If you check back after the adventure, you'll learn some stuff as well, so don't be shy to discuss your experience with your friends. <p> What ever you do, practice makes perfect. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The humble coaxial cable
Foundations of Amateur Radio <p> If you've ever used a spray can of WD-40, you might have wondered what the name means. It stands for "Water Displacement, 40th formula". In my time as a radio amateur I'd never stopped to think what the RG in RG-58 stood for. Turns out that it too has a meaning, "Radio Guide", though I have found some interesting alternative descriptions where the G stood for Government. <p> This radio guide, really a transmission line, gets a signal from point A to point B. Depending on how you construct that transmission line determines what you'll get at the other end. <p> Coaxial cable or coax is a length of cable made from several components. There's the outer layer or jacket, that protects the cable from electrical shorting, U/V deterioration and water ingress which causes all manner of problems. Inside that is an electrically conductive shield that forms one half of the transmission line, inside that is a dielectric, essentially a separator or insulator between the shield and the inner most, or central conductor, the core. <p> Each of these components can change. On the outside the first thing you might notice is the thickness of the cable. The next thing you might observe is how flexible it is. Below the outer surface other things can also be altered. For example, the core could be a solid copper wire, or it could be strands of copper. It could be aluminium, silver or even steel. It might not even be wire. Some coax like Heliax, used in broadcasting, uses a central conductive tube as the core with air as the insulator between the core and the shield. <p> The dielectric that separates the core from the shield can be made from different materials such as plastics, air and even inert gas such as nitrogen and it comes in varying thickness. Similarly the shield can vary in thickness, material and construction. There are also variations that have multiple levels of shielding, such as for example Quad Shield RG-6, common in satellite television and internet connections that has four layers of shielding. <p> Other aspects might not be nearly as obvious. If you're running coax down a power line it will need physical strength. If you're burying it in the ground it will need to be protected from water ingress. Temperature and heat dissipation are also considerations and if you're using the coax in a nuclear reactor, its ability to deal with radiation. More commonly if you need to run the coax around a corner, how tight it can be bent is another consideration. <p> As the materials and dimensions are changed, the characteristics of the coax changes. Each of these are documented and standardised. <p> The standardisation is both a blessing and a curse. So many options and so much to choose from. <p> For example, if you compare RG-58 to RG-59 they look pretty similar. If you cut into them you'll notice that they're made from similar materials. If you put them side-by-side, you'll notice that RG-59 is thicker, by about 20%, conversely the core for RG-59 is thinner by about 20%, this also means that the dielectric is about 30% different in thickness. As a consequence, connectors for one might fit on the other, but rarely work well. <p> These variations mean that while both types of coax are common and priced similarly, they're not interchangeable. RG-59 used to be common in satellite TV installations and is still used in CCTV, whilst RG-58 is common in radio communications. <p> If you made the decision to actually go out and buy RG-58, you'll come across many variations indicated by extra letters. For example, BC means Bare Copper and TC means Tinned Copper. <p> The final piece of the puzzle in this tangled offering of transmission line is that each manufacturer has their own way of doing and naming things in pursuit of market share. For example, the coax I installed recently is known as LMR-400, CNT-400, WBC-400 and several others. <p> If the performance of your coax actually matters that much, I'd recommend that you spend some time looking at your options before handing over any money. <p> All that behind the name of a piece of coax that runs between your radio and antenna. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The antenna and coax you use matter.
Foundations of Amateur Radio <p> During the week I climbed on my roof and installed a base antenna for the 2m and 70cm band. The antenna is a Diamond X-300N. It's 3 meters tall, has a gain of 6.5 dB on 2m and 9 dB on 70cm. I've owned it for just under eight years and this week I finally took it out of the box and installed it. I know, I know, in my defence, you shouldn't rush these things. <p> Truth is, until this week I really didn't have a realistic way of installing it. Several factors needed to come together. Some of them trivial, others less so. In the end, the antenna is now installed on my roof, connected via coax through my roof to my radio. <p> Now before we get all excited about what that means, let's compare my previous outdoor setting to the current one. <p> Today I'm using LMR-400 coax, 30 meters of it. Previously I used RG-58, but only 20 meters of it. <p> From a coax perspective, even though I increased the length by 30%, my loss actually went down, on 70cm it went down by over 4 dB. If you recall, 3 dB loss is the same as losing half your signal, so before my 5 Watts even got to the antenna, I'd already lost more than half of it using RG-58. <p> I will mention right now that the numbers I'm giving here are purposefully not exact. There's no point. Your situation and mine are not the same, and my two installations are barely equivalent, so actual numbers don't help you. <p> The point I'm making is that the type of coax you use to feed your antenna can make a massive difference. In my case that difference means that half of my 5 Watts never even made it to the antenna. <p> In addition to this the two antennas are different. Not by much, but enough to make a difference. As icing on the cake the new antenna is longer by a third, so my new antenna has a better horizon, it's higher off the ground, even if it's installed at a similar height. <p> You might recall that loss and gain are dependent on frequency, so any calculation needs to be done for each band you're going to use. In my case I had to do this twice, once for the 2m band and once for the 70cm band. <p> I should also mention that depending on the SWR of your antenna, the losses also change, but let's not go there today. <p> If you want to actually figure out what this means for your station, the calculation goes a little like this. <p> Take the power output from your radio, subtract the coax loss and add the antenna gain. The end result is a number that represents the gain - or loss - from the entire system. If coax loss and antenna gain are the same, you're not losing anything, but you're also not gaining anything. <p> The reward for the aches and pains from climbing on and in my roof are represented by the fact that now my 5 Watt signal on 2m effectively became 10 Watts. On 70cm it became 13 Watts. <p> With the added height and gain in addition to being able to hit all the local repeaters, I can now hear the local beacon and I've successfully decoded the JT4 and JT65 messages that the beacon spits out. <p> It's only been a week, but it's already made a massive difference. <p> No doubt my on-air experience will also benefit from this adventure. <p> Unfortunately, to do this for yourself is not quite as simple as giving you a link and punching in the numbers. I won't make any promises I cannot keep, but I am looking into it. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Buying and using pre-loved equipment
Foundations of Amateur Radio <p> The other day I received an email from Colin VK2JCC who mentioned that he was a keen home brewer and he was interested in a discussion about using ex-military gear in amateur radio. If you want to see his beautiful rig, check out Colin's Clansman PRC 320 Radio, does 2 to 30 MHz at 3 or 30 Watts. Look for his callsign and you'll also find a video of him calling CQ. <p> Colin also shared his efforts for the construction of a Ground Tuning Unit which started a whole different exploration, but I'll leave that for another day. <p> Back to the topic at hand, ex-military gear in our hobby. My initial thoughts on the subject were predictable: "What on earth do I know about this and do I have anything useful to contribute on the matter?" <p> It turns out that this isn't something new to me. You might recall that I'm an IT professional in my non-amateur life. In that role you'll likely never see me buying second hand or refurbished gear, unless I installed it myself and was the person responsible for its maintenance. <p> This same mindset prevails within my hobby. Although I am the owner of several pieces of pre-loved equipment, it arrived either because I knew the previous owner and where they live, or because it arrived unencumbered at my door. <p> I go to hamfests and look askance at the gear on offer. I'll buy connectors, a tower, but not so much anything in the way of electronics. I asked around and I'm not alone in this. Many of my peers have the same view. Why pay good money for something that has been abused? <p> It occurred to me, that this mindset is based on the idea that something can go wrong because the equipment has been invisibly damaged. Of course that is possible. However, on reflection, the reality is likely different. <p> In my professional life I've seen plenty of badly maltreated equipment. I remember being called out to a faulty computer that sat on the ground in the office in a car mechanics workshop. The computer, used for accounting, would on warm days just stop. On opening it up, in 2006, I found a motherboard with a Pentium processor on board. It was untouched from when it had been built in around 1994. The CPU fan was no longer moving and the amount of caked on dust - complete with microscopic motor oil - had formed a solid cake around the cooling fins. After removing the dirt, the fan spun back into life and the computer was once again rock-solid. <p> That is the definition of abused electronics. <p> Yes, in case you're wondering, I did recommend replacing the computer, but out in the back roads of Australia, that's easier said than done. <p> Story aside, I came to the conclusion that while abuse might reduce the circuit life from a millennium down to a century, that was unlikely to happen in my lifetime. <p> Back to the ex-military gear. <p> Based on Colin's comments, his historic radio, and my insights into the scale of abuse and their impact, I'm more inclined today than I was yesterday to investigate. <p> I will note that I'm spoilt for choice. I can pretty much buy off the shelf any gadget required, limited by my imagination and my budget, but that wasn't true for several of my amateur friends. I know of several modifications of aviation and military rigs, born from necessity, that eventually made it into amateur radio and come to think of it, there's not much difference from me adding a serial interface to my Commodore VIC 20 back in the 1980's. <p> Before I start shopping for radios that glow in the dark, there is another consideration. I did the same with computers over 20 years ago. I ended up with about a dozen of them in my office. Today that's replaced by a single one that runs as many virtual computers as I need. <p> In radio terms, do I fill my shack with boxes, or should I spend my efforts on getting an RF signal into a black box with SDR written on the side? It's hard to know what the differences are without seeing both sides of the equation, but I'm sure that at my next hamfest I'll be looking around with different coloured glasses. <p> Thank you to Colin VK2JCC for asking the question and showing his toys. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How much is a bit worth?
Foundations of Amateur Radio <p> During the week I finally made the decision to purchase my first software defined transmit capable radio. It wasn't an easy choice for me, given that the range of options vary in price from "not much" to "more than my car is worth" and an infinite number of choices between those. <p> One of the considerations, other than price, was a thing called bit-depth. In the past I've spoken about how an analogue to digital converter or ADC uses bits to represent a radio signal. In short, a voltage coming from an antenna is represented as a digital value inside the radio. No signal represents a value of zero and maximum signal represents the maximum value that fits into the decoder. A concrete example might be an 8-bit ADC which can represent 256 different values. <p> If you look at the choices available to you, you'll see that there are 8-bit radios, 12-bit ones, 16-bit, 18-bit and 24-bit radios. On the face of it you could just say, more bits is better, but how much better? <p> For example, an ANAN-10 and a FLEX-3000 radio, both costing about the same, have a different ADC. The ANAN is a 16-bit device and the FLEX is a 24-bit device. At the other end, a HackRF One is an 8-bit device and costs twice as much as an ADALM Pluto that's a 12-bit device. <p> How do you choose and what are you choosing? <p> Essentially you're choosing something called dynamic range. Think of it as the range of signal strengths that you can represent using a number of bits. <p> As it happens there's a formula for that. It's 20 times the log 10 of 2 to the power of the number of bits times the square root of 3 divided by 2 and it represents decibels relative to full scale or dBFS. <p> In more recognisable terms, it comes down to a bit being worth 6 dB of range. A good approximation is the number of bits times six plus two. <p> For example, a 6-bit SDR will have a dynamic range of 6 times 6 bits is 36, plus 2 makes 38 dB of range. An 8-bit SDR has 6 times 8 bits is 48 plus 2 makes 50 dB of dynamic range. <p> I'm using rounded off numbers here but it gives you a pretty accurate sense of scale. Six times the bits plus 2 works until about 36-bits and then it's off by one dB, until we hit 85-bits - which we won't likely be able to buy at the local ham store for a little while yet - and then it'll be off by 2 dB. <p> Another way to think of dynamic range is to think of it as the difference between the weakest signal you can measure and the strongest signal. Given your SDR is going to be using a whole chunk of radio spectrum, you likely will have to deal with your local broadcast stations as well as that QRP signal you want to decipher, so more dynamic range is better. <p> Let's give this some context. The Australian Broadcasting Corporation, the ABC, has a local AM station on 720 kHz that has a transmitter with an EIRP of just under 155 kilowatts. My QRP station uses 5 watts. My signal is 45 dB weaker than that local transmitter. <p> This means that in order for an SDR to be able detect my signal in comparison to the broadcast station, it would need to have a range of 45 dB or 45 less 2 is 43 divided by 6 is 8 bits range at a minimum. <p> Now this isn't precise or complete, but it should give you some sense of scale. <p> In this example, the amplitude range of my 5 watt signal is represented by a digital range of 1 and the broadcast transmitter is represented by a range of 255 values. <p> That means that the best you could hope for in decoding my signal would be if I was transmitting Morse, the absence or presence of my signal would make the value representing my signal go from 0 to 1. <p> As you might imagine, this is not suitable to decode something more complex like SSB. My Morse signal is also right at the noise floor, so it might not even be detectable at all. <p> Similarly, in the absence of a 150 kilowatt station, but say a 1500 watt station, you'd need just under 25 dB range, or 4-bits. <p> Now before you start pointing out that there are other issues, yes, there are, sample rate, clock stability to name two. We'll get to those. I should also point out that normally you'd represent the voltage range using both positive and negative values and I didn't mention that the maximum is calculated using RMS. <p> In the meantime, I'm getting excited to see my new toy arrive. I'll let you know how it goes. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

So, you want to be an amateur?
Foundations of Amateur Radio <p> The other day I stumbled on a social media post titled "So, you want to be an astronomer..." by /u/Andromeda321 on reddit. Look it up if you're interested how she puts together the prerequisites from her perspective as an astronomer. <p> Apart from the fact that a few of my friends are astronomers, one even a radio amateur - and I have to confess, that's a combination that is exciting and intriguing - it got me considering how you become a radio amateur. <p> In my mind I started putting together lists and links and other prerequisites that help you become an amateur when it occurred to me that being an amateur is in my view a state of mind. <p> While it's true that there is a licensing process that gives you transmission privileges, that to me is not what makes an amateur. <p> When I started my amateur radio involvement in 2010 I'd seen amateur radio exactly twice. Once as a sea-scout during a Jamboree on the Air at the end of the 1970's and once when my manager parked his tiny car, I think it was a champagne coloured Daihatsu Charade, with a massive 40m or 80m vertical in the car park at work. <p> As I started learning about amateur radio and passed my test I'd commenced the journey into what I now consider to be membership of the amateur community. That same journey is undertaken by people across the planet. For some it starts like mine, with a course. For others it starts with a neighbour or a parent, a friend or an aunt. They might start with listening to short-wave radio, or playing with electronics. <p> People start their journey at all different places and times in their life. <p> There is a perspective within the amateur radio community that says that you're not a real amateur until you've passed a test. <p> I don't think that's right. Passing a test is part of the experience and you may or may not start there, or even pursue the test. That doesn't describe your radio amateur status, that's just giving you responsibilities and regulations that permit you to expand your thirst for knowledge. <p> In my experience, the real test of being an amateur lies in something much simpler than that. <p> Being a radio amateur isn't a profession, it's a hobby. An amazing one, but a hobby. I know that there are plenty of amateurs that will argue that it's a service. I don't deny that there is a service aspect, but that doesn't take away the rest of the community, it adds to it. <p> You might wonder why I'm even bringing this up. The reason is that all too often our community erects fences. "You don't have a license", "You don't know Morse", "You only have an introductory license", "You only own a cheap Chinese hand held", followed by: "You're not a real amateur." <p> I think that you're an amateur when you decide to be one. <p> So, if you're not yet here, what's stopping you? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Permission to be curious
Foundations of Amateur Radio <p> The activities that our community places under the banner of amateur radio are many and varied. I've referred to this as a thousand hobbies in one. If you look at the surface, you'll find all manner of activities that readily attach to our hobby. <p> Activations for example are invented at any opportunity, from parks to peaks, light houses, bridges, trains, boats, lakes, roads, locators and countries. We pursue contesting, making contacts using different modes, different power levels, we pick the frequencies on which we operate. <p> If you dig a little deeper you might consider investigating propagation, or antenna builds, electronics, physics and more. <p> It occurs to me that there is an underlying activity, one that any amateur can participate in and most do at what ever level they choose. <p> It's the act of being curious. <p> You can choose to turn your radio on and be curious to what's going on around you on the bands, or you can be curious as to what the underlying principles are of the mode you're using to make a contact. You can be curious as to the electrical principles and you can be curious as to the maths behind that. <p> Superficially you might think that being curious isn't really something that is remarkable. I'm here to disagree with that. <p> If you drive a car, you can choose to be curious, but many just put fuel in the right hole and keep air in the tyres. Most will wash their car from time to time. Some will dig into the innards of their car, but the vast majority lacking even a superficial understanding will have their car serviced by an expert. The same is true for computers. You might not wash your computer, but doing maintenance is often a case of waiting for it to die and calling your local IT expert. <p> There is absolutely opportunity for curiosity in relation to cars and computers and there are plenty of stories from those who follow that path. <p> In our community I think that this balance is completely different. In amateur radio there are a few people who use their radio like the majority of the general public uses their car, but in the whole, I think that the bulk of radio amateurs travel down a rabbit hole on a regular basis, armed with multi-meters, screw drivers and soldering irons. I see their reports, I hear their questions, I read their emails and respond to their requests. <p> You might say that I'm biased, since those are the amateurs I come across, but I think that's underselling quite how special this hobby of ours really is. <p> I love that you can be curious about an antenna and keep digging and become curious about the underlying laws, right down to the fundamental principles behind the phenomenon we experience as radio. <p> I've said many times that getting your license is like receiving the keys to the hobby. You have the ability to open the door and come inside to see and explore for yourself. <p> What have you been curious about lately and what did you do about it? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

First ever digital contact!
Foundations of Amateur Radio <p> When you start life you learn early on the difference between being told about an experience and the actual experience. There's a saying that comes to mind, I use it regularly in my day job: In theory there is no difference between theory and practice, while in practice there is. <p> I thought I'd do the quote justice to see where it came from, not from Einstein, who was three years old at the time it was coined and neither Yogi Berra or Richard Feynman had been born. Quote Investigator puts it in the Yale Literary Magazine of February 1882 and attributes it to Benjamin Brewster, but I digress. <p> A little while ago the regulator in Australia altered the rules of engagement in relation to amateur radio for people holding the license that I do. All Australian amateurs are now permitted to transmit digital modes. Not that this should have been any impediment to the exploration of the receive side, but I had a few other things on my plate to try. Still do. <p> Over the weekend I sat in my driveway with my radio and had the urge to see if I could actually do some PSK31, a digital mode that had a low entry barrier, since there were defined frequencies, and I could use a decoder on my phone. <p> So, I set about doing just that. I had already programmed in the various frequencies into my radio the week before. I hadn't actually heard any signals, but that didn't deter me. I set about getting myself set-up for what I'm calling a driveway hack. <p> Picture this. A folding table with my radio. A stool next to it with me on it. The radio connected to an antenna, a vertical that was attached to a neighbour's roof with a magnetic mount and my phone running DroidPSK. I was tuned to the 10m PSK frequency, had the volume turned up, holding my phone next to the speaker, watching the waterfall. <p> Nothing. <p> I called up a mate who had this all working and we set about trouble shooting my set up. <p> He made some transmissions; nothing. <p> I listened to the 10m beacon, loud and clear. <p> He made some more transmissions, still nothing. <p> Then we realised while I was switching back and forth between the beacon and the PSK frequency that his radio was set up for a different standard PSK frequency. Gotta love standards, there's one for every occasion. Changed my frequency and for the first time I could actually see stuff in the waterfall display on my phone. <p> If you've never seen a waterfall display, it's a tool that helps visualise the signal strength of a chunk of spectrum over time. It's pretty nifty and a waterfall displays a lot of information. <p> Starting with colour, the idea is that a colour represents a particular signal strength. Red for full signal, yellow for half, blue for the lowest detected signal and black for no signal. Fill in the gaps with the colours of the rainbow. <p> If you represent a line made of dots with the start of the line at say 0 Hz and the end of the line at say 3 kHz, you could split the line into 300 dots, and each dot could be coloured to represent the average signal strength for a little 10 Hz slice of spectrum. <p> If you wait a second, move the line you drew down and then measure again, you'd end up with two lines. The line from now at the top, the line from a second ago below it. If you do this every second, you'll end up with lines flowing off the bottom of the screen, the oldest lines at the bottom and the newest ones at the top. <p> That is a waterfall display. Over time you'll start to recognise what a particular signal looks like on the waterfall and there are even modes where you can draw on the waterfall, but I'll leave that for another day. <p> As I said, I could now finally see signals on my waterfall display. <p> I'm not going to dig too deep here, because there's much confusion in the language surrounding all this and I intend to get the names straight in my mind before I express them here, but after figuring out that you have to tell DroidPSK which signal you want to decode, I finally managed to decode the transmission from my friend. <p> After putting on some headphones and realising that the clicks I was hearing from my phone were actually artefacts from the speaker, I also managed to transmit a CQ signal which my friend decoded. He then acknowledged my callsign in his next transmission. <p> So, I now have two screen shots, his and mine, showing that we both saw each other using 10m PSK31. There wasn't a signal strength exchange, mainly because I have yet to figure out how to determine that and where it's visible, but for all the things that matter, I managed a contact with PSK31 thanks to Randall VK6WR, very exciting! <p> Since then I've started experimenting with decoding WebSDR, that's HF signals coming in via the internet and being decoded on my computer from the web audio. I'm still working on that, but there is so much to learn and play with and a transmitter isn't yet needed to have fun. I should mention that you can also decode satellite signals like this. <p> Digital modes, just when you thought that the rabbit hole couldn't get any deeper. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

When was the last time you played?
Foundations of Amateur Radio <p> The other day it occurred to me that my callsign had been away from HF for months, probably longer. I didn't really want to think about how long it had been. I moved QTH over two years ago and ever since I've been working on a new antenna set-up. You know the kind, you shouldn't rush this. Anyway, having just had a camp-out with some friends for a portable contest, where I gleefully had fun with the station callsign, I thought it was time to actually do what I keep advocating to anyone who stands still long enough, to get on air and make some noise. <p> So I did. <p> You know that feeling when the longer you wait, the harder it gets and the more you put it off? That had invaded my thinking and my avoidance. The typical excuses of not enough space, too much noise, no antenna, radio not ready, too hard, all fought their way into prominence. I'd had enough. <p> So, on Saturday I collected all the bits that make up my portable station. It had clearly been a while since I'd used it, since I couldn't for the life of me remember where the head of my Yaesu FT-857d was, that was until I remembered that it had previously been installed in my car, so that's precisely where I found it. The tiny jumper cable between the head and the body was located in my headset bag where I'd stashed it after forgetting it for a contest one year. The microphone was where I'd stored it in the car. The battery was easier, since I'd used that the weekend before. Pulled out a table, a chair and set about putting my station together right there in the driveway. <p> I'd been meaning to test an antenna that to all intents and purposes was doomed to fail, a long-wire on the ground. I didn't have an un-un or a balun, but I did have my trusty antenna coupler, so I used that. One end of the antenna, twelve and a half meters going one way, the other half going at a right angle. That pretty much solved that. <p> Then for the final touch, I turned the radio on. All worked and I set about figuring out what I could hear. Across all the NCDXF beacons and bands I could hear the local beacon about 30km away. <p> I have mentioned the NCDXF before, but in short, the Northern California DX Foundation has since 1979 coordinated the installation and maintenance of a collection of transmitters that 24 hours a day, every three minutes transmits on a staggered schedule across 5 different bands. It's called the International Beacon Project. For funding, the NCDXF relies on donations from people like you and in Western Australia the WA Repeater Group maintain the beacon, VK6RBP. <p> Each transmission consists of a callsign, a beep at a 100 watts, a beep at 10 watts, 1 watt and 100 milliwatts. You can hear the beacons on 20m, 17m, 15m, 12m and 10m. Their purpose is to determine what propagation is like across the world on each of the bands, in pretty much real time. It was the impetus for me to start learning Morse Code - in case you're wondering, no, I know, I'm still at it. <p> On my wire on the ground antenna the local beacon on the 10m band was by far the strongest. I also had a listen on 80m and 40m and even found two stations in deep discussion about something or other. Didn't manage to catch their callsigns, but good readability, not so much in the way of signal strength. <p> I called up a friend on 900 MHz, in case you're sceptical, yes I hold a licence for that, so do you, it's cunningly encapsulated in a sophisticated portable battery powered multifunctional gadget made of electronics and glass. He was in the middle of repairing some damage sustained to his G5RV Jr. antenna during our latest adventures - Hi Glynn - and afterwards we had a go to see if we could in fact hear each other. I was using 5 Watts, he something like 70 Watts. Neither of us could hear the other, even though we're a similar distance from each other as the beacon. Not yet sure if it was his radio acting up, or mine for that matter. <p> I then started down the digital modes path. Installed a PSK31 decoder and set about programming my radio for the traditional PSK31 frequencies. Didn't hear anything, didn't decode anything, but had a ball none the less. <p> You might think to yourself right about now what the point of all this was if I didn't make any contacts? The answer is simple, I got outside, in the sun, soaked up some Vitamin D and played radio, just like the weekend was intended for. My next adventures are likely going to involve the same antenna and a vertical for transmit to see how that goes. <p> You don't need an excuse to get out and play and when you do you might not make any contacts, but that's not really the point of playing, is it? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Breaking the isolation one QSO at a time.
Foundations of Amateur Radio <p> In our hobby we regularly talk about its purpose, its need, its usefulness and other potentially abstract notions. Often there's a nod towards science, learning, self-discovery, challenge, emergency service or some other higher order concept. I know I've discussed many of those over the years and encouraged you to find what the hobby means to you. <p> There is one aspect of our hobby that's pretty much left unsaid. It's left unsaid because it's obvious, since radio is about communication at its heart, the idea that we use our radios for communication is ingrained and unheralded. You might find a few new amateurs talking about how they made their first contact on the local repeater, or how they want to use the hobby to stay in touch when they're out and about. <p> It occurred to me the other day that much of the world is subject to travel restrictions and social or physical distancing requirements. There's places that are in total lock-down and whilst there are strong recommendations for people over 70 to stay completely isolated, that's not yet a requirement where I live. It might come to that, but at the moment the COVID-19 pandemic is changing habits and communities on an hourly basis. <p> Technology is often sought as a solution. There's plenty of video-conferences being held. Local amateur clubs are going online to stay in touch with members while face-to-face meetings are off the menu. Then there's the ongoing access to social media, blogs, discussion groups, mailing lists and the like. <p> There are a few brave radio clubs using something a little less technical. The radio. Shock, horror, imagine that, an amateur radio club using an actual, you know radio, to talk to each other. I must admit that communication via radio, as obvious as that sounds isn't always the first thing that comes to mind. I've lost count of the number of times when at the local club one member stood outside yelling back into the shack which way the rotator on the Yagi was pointing whilst adjustments were being made - turns out that the rotator was spinning on the mast in the wind. Took a concerted effort, seriously, to actually turn on a hand-held radio and talk to each other, like civilised people. <p> On the weekend during F-troop, a weekly net for new and returning amateurs, I also asked how people were doing given the social isolation that is pervasive. <p> I also started toying with the idea of running an F-troop every day, then I scaled it back to every Wednesday and Saturday and then it occurred to me that the power to host a net is in the thumb of any amateur clicking their push to talk button and I finally settled on continuing the normal activity of hosting F-troop on Saturday morning at 00:00 UTC for an hour. <p> I understand that in a technically connected world with cheap internet and fully functional gadgets like smart phones, the idea of going back to radio might seem like a step backwards, but I'd like to point out that we're radio amateurs. That's like being a chef and ordering take-out when you have a fully stocked kitchen. <p> If you're experienced in this hobby you'll know that nobody needs to grant you permission to host a net, but if you're new here you might not. So, to you I say: "You don't need permission to host a net, so get to it." <p> There are some things I've learnt since starting F-troop nearly a decade ago. Start small. Depending on the skill-level of the participants, choose an option for hosting it. F-troop is run with a single net-controller, often that's me, and the role of net-control directs who's next to talk. If you're just playing around, the tried and true version is a round-robin net. You'll need to pay attention a little better because you'll need to know who comes after you so you can hand the call to them. There are also variations on this, but again, start small. <p> I track contacts in a spreadsheet, but a piece of paper is just fine. Writing down all the stations you hear is a great idea, since it helps you keep track of who's said what. You can add information as it comes to hand. If the net is on HF you might record the signal strength you see when you're listening to each station, as well as the name and location or QTH. <p> Pro-Tip, use a new piece of paper for each net and put a date on it. Future you will love you for it. <p> My point is that there should be absolutely no impediment to getting on air, making noise and breaking isolation from the comfort of your own shack. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Listening from the ground up
Foundations of Amateur Radio <p> When I started learning about antennas I was told height is might. The higher the better. For many years I've followed that advice and like a good little parrot I've dispensed that advice. Turns out that as is usual in our hobby, that's not the whole story. <p> I first came across a ground based antenna with a BOG, that's a Beverage On Ground antenna. It's essentially a long length of coax that's pointed at what you want to hear. You can either terminate the end, or not, different effects result with plenty of discussion about directivity, angles, lobes and the like. <p> One of the things you'll notice with you use a Beverage antenna is that it's quiet. All signals are reduced in strength, but that also means that noise is reduced. Turns out that this pays off and you hear stuff that you've not heard before. Excellent for a field day or if you want to hear some serious DX stations. <p> There's plenty of stuff that's not nice about a Beverage antenna. For one, it's highly directional, it takes up lots of space and if you want to listen in another direction, you'll either build a second or third and switch between them. That, or you'll be rolling up and laying out the coax to point at a new DX entity. <p> You also cannot transmit with a Beverage antenna. While we're on the subject, often a beverage can be combined with a vertical, one for receive, the other for transmit. It's one of the projects that lying in my to-do pile. I've even got a remote controlled coax switch, but I'm still figuring out how to make my FT-857d do the switching. <p> I could stop there, but I came across another idea a couple of weeks ago. At the time I was being introduced to the local emergency communications team. They showed me their HF stand-by gear. Long piece of wire that you could chuck out on the ground and make contact. As a good little amateur I remember thinking to myself, these poor people they have a lot to learn. I'm glad I'm an eager apprentice in learning the art of keeping my big mouth shut. <p> During F-troop, a weekly net for new and returning amateurs, you'll find details on vk6flab.com, another amateur was talking about putting a wire near the ground, like about a foot off the turf with great results. <p> I tried it on the weekend with a friend. We were out camping for a local amateur contest, miles from anywhere and anyone and I recalled the emergency communications people and the story during F-troop. We had some time to play, so we started with a long-wire, actually, pretty-much a wire dipole on the ground. Plugged it in, turned on the radio, magic. Same kind of sound effect as a Beverage antenna. Nice and quiet, good signals to be heard. We turned the whole contraption 90 degrees, no difference. Since then I've learned that it's pretty much omni directional and unlike a Beverage antenna, you can use it to transmit. <p> Of course it's not going to act in quite the same way as a dipole high in the air, and that's pretty obvious, since it's not in the air. It'll give you communications that are called NVIS, or Near Vertical Incident Skywave, essentially stuff that goes straight up and comes down, stations up to about 400 km or so away. For scale, that's enough to cover all of Holland. In Australia it's enough to cover the state of Victoria, or the width of the UK, and most of the width of the State of New York. <p> Before you get all huffy and point out that this is not a great DX antenna I'll beat you to it and tell you that this is not a great DX antenna. It's not meant to be. Nor is it intended to be an instruction on what antenna to build next. This is purely intended to illustrate that antennas come in all manner of shapes and sizes and there is lots to be learnt from trial and error. <p> I know that this is a "compromise" antenna. Guess what, so is every other antenna. Today the compromise is that we don't need any poles, trees or unsuspecting human support structures to keep an antenna in the air. You can essentially try this one for free at any time, on your own, on the beach, in a park or on the side of a mountain. <p> Another great use is to talk to your friends who live in the same city on HF. I have no doubt you could even manage some FT8 contacts using this antenna. <p> Next time someone tells you to put your antenna in the air, ask them who they want to talk to. If it's locals, then there is absolutely no need at all. As for mastering the art of keeping my big mouth shut, we'll see. <p> I'll leave you with this. It's not the answer that's important, it's the question, for everything else there's experimentation. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

What level of preparedness are you at?
Foundations of Amateur Radio <p> An often repeated statement about the purpose of our hobby is related to emergency preparedness. The various peak bodies around the world devote plenty of resources to the concept, with helpful examples, umbrella organisations, training, coordinators, grants and funding, photo-opportunities and all the other trimmings that come from the idea that you and I are going to be of assistance in the case of some or other emergency. <p> Looking up the various emergency coordination groups is a disappointing experience. From broken web-sites with non-existent pages to latest news that's over two years old, through to the latest sausage sizzle and fun-run. Entreaties to make sure that you have your current Membership ID card, otherwise you won't be covered for insurance purposes. As I said, all the trimmings with lots of evidence of paper pushing and little or no evidence of actual preparedness, let alone public information that might help any new or old radio amateur become prepared. <p> Back to the topic at hand and leaving aside the nature of the emergency for a moment, given that the response for a bush-fire, a cyclone, flood or pestilence is likely to be different. <p> Let's look at the things we have direct control over. <p> If you have at any time taken your radio out of the shack and carried it into a paddock, connected it to an antenna, fired it up and made a contact, you're well ahead of the curve. <p> There are plenty of amateurs who have never ever considered what going field-portable might look like, let alone tried it. That's fine if you live in a bunker, have independent power and are able to withstand all manner of disaster scenarios, but realistically it likely means that your emergency assistance will be of the kind that's outside the emergency zone. Helpful to be sure, but there's plenty of those stations to be found - unless the issue is global, in which case we have a completely different set of problems, pandemic, anyone, anyone? <p> Let's focus on the other side of the fence. <p> You're in an emergency zone. Doesn't matter what kind of emergency. Communications are limited or overwhelmed, information is restricted, messaging is hampered and you're a radio amateur with a working radio. If all goes well you should be able to help. <p> So what does a working radio look like and what does helping mean? <p> First thing to think of is power. Have you got a battery? Is it charged? When was the last time you tested it? How long has it been sitting on the shelf? Did it discharge in the meantime? What about a charger? Have you got a generator? What about fuel and oil? What about spare parts? Have you got something else, like a solar panel, a wind generator or a water turbine? What about a push-bike with a dynamo attached? How long does your radio run on a battery and at which transmitter power level is that? <p> After thoroughly investigating power, what does your actual emergency station look like? Will it be used for voice communication, or will it be used as a digital gateway? Can you use it to send rudimentary messages, or can it be used as an internet gateway for a local community? <p> What bands are you planning to operate on? Do you have an antenna? What happens if your current antenna is taken out by a fire, lighting strike or something else? When was it last tested? Do you have a back-up antenna? Have you actually used this antenna? Does it have all the right connectors and are they with the antenna? <p> So, pretend that you got all that right. What about you? Have you got spare clothes? Food? Shelter? Medication? What about Personal Protective Equipment, masks, gloves, what-ever? What about ancillary items like pen and paper? Do you have power for the laptop that's being used to create the digital mode messages? <p> Note that I've not said a word about the usefulness of any of this. This is the base level of preparedness just so you can actually look yourself in the mirror and say that you have at least got a level of ability to be of assistance in the case of an emergency. <p> You can of course argue that you should hook up with the local emergency services and offer your skills as a radio amateur. That's helpful, but what if you cannot actually go to the muster point? How does that help? <p> Now lets pretend that you actually have done all this. When was the last time you tested it? <p> What does the actual helping look like? <p> Have you ever attempted to pass emergency messages? What about messages that must be transferred absolutely 100% correctly, think medication dosages? Who did you pass them to? When was the last time you did a regional emergency simulation between your amateur friends? How often do you do this? Once a decade, or more often than that? What if the local repeater isn't working? What about in your club or your local neighbourhood? Do your neighbours even know you exist? <p> The point of all of this is to reveal that the level of emergency preparedness for radio amateurs is in my opinion spotty at best. If you disagree with me because you are prepared I'd like to ask if you helped prepare your local amateur community and the wider community around it? I don't doubt that there are individuals, even groups who are prepared, but I suspect that they are far and few between. <p> When was the last time you actually went into the field for a week and played radio, for real, battery only, limited resources, no outside help? <p> I'd love to believe that this is universal, but you and I both know that there is plenty more to be done. How realistic is your emergency preparedness and what are you going to do about it? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

On the shoulders of giants we stand.
Foundations of Amateur Radio <p> One of the things I love most about this hobby is the ability to randomly dart off into any related direction and learn new stuff. For example, the names Nikola, Guglielmo, Heinrich and Edwin emblazoned on a t-shirt sent to me by a very appreciative listener Jack KI4KEP, started an exploration into the deeds and misdeeds of the people behind those names. <p> The first three might be somewhat familiar, Nikola Tesla whom we have to thank for inventions like Alternating Current, the Tesla coil, wireless power, radio remote control and many others. The Tesla company is named as a tribute to him. The magnetic flux density uses the letter T as its symbol and its called the Tesla. <p> As a side note, if you've ever struggled to decide if a symbol needs to be a capital letter or not, like say the V for volt, the A for ampere, the O for ohm, the m for meter, the s in second or the K in kelvin, you just need to remember that if the unit is named after a person, the symbol needs to be a capital letter. That does assume that you know that the unit is named after an actual person, like say the Earl of Sandwich. <p> Name two in our list, Guglielmo Marconi is the person whom we can thank for the practical development of radio communication, using improved spark-gap transmitters, the development and commercialisation of long-distance radio transmissions and his association with many other services such as a transatlantic radio-telegraph service, providing communications to shipping such as Jack Phillips and Harold Bride who were employed by the Marconi International Marine Communication Company to act as radio operators on the RMS Titanic on its fateful voyage. <p> Our third name, Heinrich comes into sharp focus when I add his surname, Hertz. His name continues on in our day-to-day language and Heinrich Hertz is responsible for validating many of the underlying principles of our hobby. Using a spark-gap transmitter he was the first to conclusively prove the existence of electromagnetic waves which were predicted by James Clerk Maxwell. He also came up with the parabolic antenna, the dipole antenna, measurement of electric field intensity, electromagnetic waves and many other experiments. If you've ever seen a bullet hole in glass, you've seen a Hertzian cone. <p> The last name had me stumped. It took a question to learn that Edwin shares a name with a famous cyclist and a famous astronaut, namely Armstrong. Edwin Howard Armstrong has been called "the most prolific and influential inventor in radio history". <p> If you're like me you may not have heard of Edwin Armstrong. You might be surprised to learn that he's responsible for the regenerative circuit, the super-heterodyne circuit and while he was working on defending his invention against a claim made by a patent attorney he stumbled on the super-regeneration circuit. If you're a radio amateur, you'll likely have heard those terms, if not, they're electronic circuits that make radio receivers more sensitive which forms the basis of many radios in use today. My Yaesu FT-857d is a super-heterodyne radio for example. <p> It doesn't stop there. The biggest claim to fame that Edwin Armstrong brings to the table is the invention of FM radio. It took many years and a protracted lawsuit that lasted until almost a year after he died to finally have Armstrong formally established as the inventor of FM. <p> Not for a minute will I suggest that my exploration was comprehensive or in-depth, but it made my day when I put on a t-shirt with the names of those inventors who made it possible for me to be here and share this with you today. <p> On the shoulders of giants wearing a t-shirt with their names I stand. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

All bands + All modes + All countries
Foundations of Amateur Radio <p> A regular lament is the lack of things to do in our hobby. I know, it's foreign to me, but there are plenty of amateurs who express frustration at the lack of activity, no contacts, nothing new, no challenges. <p> For my poison, I started the process of contacting 100 different countries using 5 Watts. I've been at it for a number of years and truth be told, since my latest domestic move, over two years ago now, my efforts have been put on hold. Not because I didn't want to, but because I was getting annoyed with having to leave my home and wanting desperately to have a functional shack at home. As you might know, that's a project that's still in hand and thanks to some magnificent assistance from various places, I'm still making progress. <p> That said, your perspective might be dulled by the notion that this pretty much concludes the on-air activity possibilities that exist. Within my own license class, until recently, I was permitted to use voice modes like SSB, AM and FM and I was permitted to use hand-keyed Morse. I have access to 10 Watts and am currently allowed to use six different amateur bands, namely 80m, 40m, 15m, 10m, 2m and 70cm. So together with the four modes, I'd be able to make 24 different contacts to 100 different countries, that's 2400 different combinations. <p> Of course there are more than 100 countries, that is, DXCC entities. The 2018 list has 340 of them, so that's over 8-thousand different options for getting on air and making noise. <p> Last year all that changed. The local regulator in Australia, the ACMA decreed that all amateurs in Australia were permitted to use all modes. <p> It's taken a little while for that to sink in. Specifically what it means for me. <p> A quick search reveals that there are at least 60 different digital modes, think RTTY, Olivia, PSK31, etc. In addition to those, there's a plethora of other modes like IRLP, AllStar Link, EchoLink, CODEC2 and Brandmeister. <p> So conservatively I'm going to estimate that I now have got access to over a hundred different modes, across six bands with 340 countries, that's over 200-thousand different options for making a contact. <p> Of course it's unlikely that I'll make a contact between say Belize V3A and Perth VK6 on 2m using Olivia, but even if we limit our calculation to HF, we still have at least 136-thousand opportunities for adding something interesting to your logbook. <p> I've been hunting for a canonical list of all the various amateur modes and the tools needed to make and receive them. No doubt that will take me some time. I'll be documenting it on the projects page on vk6flab.com if you want to follow along. Speaking of which, you'll also find past episodes of this podcast there. <p> I suppose I should start by converting my current efforts into some pretty pictures that show what I've been up to so far, but that's a mapping exercise that I'll have to add to my to-do list, since I'm guessing it involves learning how to use some fun mapping tools. <p> If 136-thousand opportunities isn't enough, you can also add grid-squares, large and small, different prefectures in Japan, provinces in the Netherlands, CQ zones across the world or ITU areas, prefixes and operating modes. <p> Clearly there's plenty to do and see. <p> I wonder if there's an award for all modes all bands all countries and I wonder what happens if someone invents a new mode? <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The impersonal nature of digital and other myths
Foundations of Amateur Radio <p> The other day I bumped into a concept that I've heard repeated before. The so-called "impersonal nature" of digital modes. <p> There's this idea that any communication that isn't using voice, is devoid of the human touch. Often this assertion is specifically made in relation to modern digital modes like JT65 and FT8. As an aside, I've never heard it in relation to other digital amateur modes like slow-scan television, RTTY or PSK31. <p> In the early 1900's when amateur radio was beginning to be a thing, the means of communication was Morse Code. With beeps across the globe contacts were made between amateur stations. With every incoming dit and dah, letters were received, words constructed and meaning derived. This is long distance communication in its early stages. <p> Each amateur was said to have a fist, their particular rhythm of touching the key. Across multiple stations it was possible for an experienced operator to distinguish between two amateurs based on how they were sending Morse Code. I can confirm that if you've ever had the privilege of hearing lots of amateurs clamour in a so-called pile-up, you can hear for yourself that different stations sound different, even if they're all sending Morse Code. <p> So on the one hand we have this deeply inhuman means of communications like Morse Code which is by the language we use considered to be made by humans, personalised with a fist. On the other hand we have a deeply technical mode like FT8 which isn't. <p> During the week I was discussing this change of perception during a haircut. I pointed out that this happens everywhere. For example, in the hairdressing profession an electric clipper might have been seen as impersonal when it was invented in 1921. Today it makes quick work of a Number 1 cut. In mobile phone communication an SMS was seen as impersonal with voice preferred, but today the world would look quite different without the 5 billion messaging mobile phone subscribers. In 2013 it was estimated that there were 8 trillion SMS messages, and 10 trillion other smart phone messages. As you might realise, behind each of those messages is a human, well, apart from the SPAM and the computer notifications, but even those are programmed by a human. <p> So what makes the difference between Morse Code and FT8? Why is an SMS impersonal in 1992, but preferred by most today? <p> I'd hazard a guess and state that the experience of the person making the statement has a lot to say about their perception of the nature of the medium. <p> My typing away at a keyboard and seeing words appear on my screen might not appeal to someone who chased a turkey around the yard in search of a quill, but then electricity might also be surprising. <p> It's interesting to me that PSK31, something that's not particularly thought of as being impersonal, was introduced to the amateur radio community in December 1998 by Peter G3PLX. The first Weak Signal modes, commonly known as WSJT modes, were introduced in 2001 by Joe K1JT, only three years later. JT65 came around in 2003. We have this situation where PSK31 is not impersonal, but JT65, which is five years younger, is considered impersonal and the popular mode FT8, which is an extension of JT65 is said to be the end of the hobby. <p> If hyperbole would relate to truth, the end of our hobby in sight, we should all get rid of our radios and hand back our licenses. <p> Perhaps we should take a step back and notice that behind every FT8 station, behind every voice-call, behind every amateur transmitter is at some point a human with a license. If we're splitting hairs, then a local automatic voice repeater must be the height of impersonal. <p> The other thing I'd like to point out is that how you perceive the use of a particular mode is also important. If you think of FT8 as having a personal beacon in your shack that uses your radio and your antenna to measure how well your signal is heard across the globe, you might just start enjoying this so-called impersonal mode. <p> One of my friends, Wally VK6YS, now silent key, told a story where he was driving down the highway to meet his friend. They were chatting away using Morse Code, Wally in his car, the friend in his shack. Once Wally arrived the friend wanted to see how Wally was able to send Morse Code whilst driving and could he please see his Morse key? Wally confessed to having whistled into his microphone to make the contact, since he didn't have a Morse key in his car. According to Wally, his friend was off the air for months in disgust. <p> I should mention that my Number 1 haircut looks great, if only for the fact that it allowed me to spend some quality time discussing and contemplating the nature of the hobby that I love. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

The chicken and the egg, which comes first, the antenna or the radio?
Foundations of Amateur Radio <p> In my day to day activities as a radio amateur I come in contact with people across all parts of their amateur journey. Some who don't yet know that they're amateurs, through to those who've just passed their test and are waiting for their callsign. Then there are those who have been amateurs for a while, experimented a bit and have settled down into the comfort of being a member of an active community. Stretch that further and I also spend regular quality time with amateurs who have been licensed longer than I've been alive. <p> Recently I received an email from a freshly minted amateur. Just like me, still pretty much wet behind the ears, keen as mustard, trying very hard to figure out what to do next and where to go. <p> The basic gist of the email from this amateur was that they didn't know what kind of antenna they could erect at their home and failing that, couldn't decide on what radio to acquire to match the antenna that they hadn't decided on, not to mention that the antenna needed to match the radio that didn't yet exist. <p> If you've been around this community for a while you might recognise the chicken and the egg, which comes first, the antenna or the radio? <p> The answer is obvious, hidden in plain sight, easy to deduce, simple to understand, and completely useless. <p> Let me help you with the answer: It depends. <p> If that didn't test your patience, even if you've been an amateur for longer than my parents have been alive, you'll know that this is an unanswerable question. <p> So how do you break the egg and get started? <p> Easy. <p> Start somewhere. <p> As it happens I have a recommendation. It's cheap, simple and it will get your feet wet sooner rather than later. My recommendation is neither, or both, depending on your perspective. I promise, I'll get to the point shortly. The reason I'm making it last and savouring the point, some might say, belabouring it, is because it's one that happens over and over again, day in, day out, year in, year out. <p> My recommendation is that you spend $25 on an RTL-SDR dongle and hunt around your home for a piece of wire. That's it. <p> If you're not familiar with an RTL-SDR dongle, it's essentially a USB thumb-drive sized device that plugs into the nearest computer and paired with the correct software it has access to many if not all of the frequencies that you as an amateur are allowed to play with. <p> Given that it's a receiver, the antenna doesn't really matter all that much, at least not initially, so any piece of conductive wire will suit. Most dongles even come with an antenna of sorts, so you can get started straight away. <p> Resources associated with this podcast are on the vk6flab.com website where I've also collected a few links under F-troop to get you on your way with an RTL-SDR dongle. <p> The purist radio amateurs will likely arc up at this point and mention that this isn't real amateur radio, to which I can only say: Bah Humbug. Radio is about receiving as much as it is about transmitting. Any fool with two bits of wire can transmit, but it takes finesse to receive, so start there. <p> There are other benefits from going this way. Other than ease of entry, that's another way of saying - cheap - you can easily spot where and when there is activity. You can use all the traditional modes like CW, SSB, AM and FM, but you can also play with all of the new modes like WSPR, FT8, JT65 and investigate some of the other modes like RTTY, PSK31, Olivia, SSTV and others. <p> All this will help you have a better idea of the landscape you're stepping into without a major purchase. <p> To really set a cat among the pigeons, I'm also looking into a Raspberry Pi based transmitter, rpitx by Evariste F5OEO. When that bears fruit I'll let you know. In the mean time, play, learn, listen, experiment. No need to spend hundreds or thousands of dollars while you're still unsure. <p> Even if you already have a lovely amateur station, an RTL-SDR dongle is worth every cent and then some. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

Exploring an understanding of filters and circuits.
Foundations of Amateur Radio <p> Every person is the product of their environment. Unsurprisingly this is even true for radio amateurs. That's not too say that we can't break our mould, but it takes effort. I grew up around technology in the 1980's. As a result I'm familiar with 8-bit microprocessors like the Motorola 6502 which featured heavily at the time. I tend to think in terms of the presence or absence of a signal, rather than the intricacies of circuits and components. <p> As a child of my time, I'm not particularly familiar with the punch card or paper tape, or core memory, or valves, 386 machine code or what's in an FPGA. As a direct result of my age, my knowledge and understanding of circuits is sparse at best. I understand basic components like resisters and capacitors in a DC setting, Ohms Law and the fun you can have with a battery, a few resistors, diodes and an LED light. <p> As a radio amateur I've been introduced to how some things work differently in an AC circuit, like an antenna and a feed-line. <p> Until very recently my knowledge about filters was based on what I'd read. I know that there is fun to be had with coax and stubs and other cute things, but how and why they work eluded me. Today I'm a step closer. <p> Before I dig in and share some of what I've learnt, let's have a quick look at what a filter is and does. You'll have likely heard of high-pass and low-pass filters. You might have heard of band-pass and band-stop filters. <p> If you think of a high-pass filter as a device that lets through high frequencies and a low-pass filter as a device that lets through low frequencies, we're already well on our way. If you put a high-pass filter together with a low-pass filter, you end up with a range of frequencies that doesn't pass, known as a band-stop filter. <p> Similarly, if you tweak the frequencies that pass just so, you can combine a high-pass and a low-pass filter to make a band-pass filter. <p> Let me illustrate. <p> Imagine a 15m band-pass filter. It allows all frequencies in the 15m amateur band through, but blocks everything else. You could construct such a thing from a high-pass filter that allows 15m and above through combined with a low-pass filter that allows 15m and below through. Everything below 15m is stopped by the high-pass filter and everything above 15m is stopped by the low-pass filter. The gap between the overlap of the high-pass and low-pass filters is what creates a space where the 15m band gets through. <p> If you move things around a little, the same can be constructed to make a 15m band-stop filter. Something that lets anything through, except a 15m amateur signal. To make such a gadget would require a low-pass filter that allows everything below 15m combined with a high-pass filter that lets everything above 15m through. <p> So, if you can construct a high-pass filter and a low-pass filter, you can pretty much create any combination and allow or stop specific frequency ranges. <p> If you're wondering why this might be useful, think about a contest. Two radios in the same shack. One transmitting on 15m and one on 40m. These two bands, one at 21 MHz and one at 7 MHz are third harmonics to each other. This means essentially that a radio on 40m affects one on 15m and vice-versa. If you had a set of filters that stopped 15m and passed 40m on one transceiver and a set of filters that stopped 40m and passed 15m on the other, both of you would be much happier. <p> You don't need to do contesting to benefit from a filter. If you use an RTL-SDR dongle, it's affected by nearby strong signals, like say a local radio or television station. That's fine if that's what you're trying to hear, but not so much if you're trying to hear something else. Filters can help to make your life better. <p> Now, to round this off at a suitable point, you can think of an inductor as device that lets low frequencies through but blocks high frequencies. Similarly, a capacitor is a device that blocks low frequencies but lets high frequencies through. So, it's fair to think of an inductor as a low-pass filter and a capacitor as a high-pass filter. The symbol for a capacitor is the letter C (Charlie) and for an inductor it's the letter L (Lima). <p> You could make a circuit that either directly blocks from a certain frequency, or one that lets it through, but sends it to ground. This gives you two designs for a low pass filter one using an inductor or an RL circuit and one using a capacitor or an RC circuit. Similarly you can create a high-pass filter using either an inductor or a capacitor. That gives you four designs for two filters. <p> Each of these can be combined to create band-pass and band-stop filters. <p> The maths behind it isn't particularly daunting with basic high-school maths and if you want to see it happen before your eyes, check out the "Organic Chemistry Tutor" on YouTube. The play list you're looking for is cleverly disguised as "Electronic Circuits". <p> As a direct result, I started hunting for breadboards, but it turns out that you can simulate these circuits online using any number of simulators. Of course there's going to be a gap between simulation and reality, but that's when you get out your soldering iron. <p> Remember, if you smell chicken, you're holding it wrong. <p> I'm Onno VK6FLAB
Listen: podcast - audio/mp3

How I care for my connectors
Foundations of Amateur Radio <p> If you've ever found yourself in the position of attempting to screw a PL259 into an SO239, or an N-type plug into an N-type socket you'll have likely come across the situation where the thread doesn't quite fit. If it does, you might have issues attempting to undo the connection, even if you didn't particularly do anything strenuous in relation to mating the two in the first place. <p> This kind of situation happens to me more than I think is reasonable. It happens on cheap connectors, on expensive ones, on the back of radio gear, on adaptors, patch leads and the like. <p> Initially I put this down to cheap vs. expensive, but that really doesn't add up if you're attempting to connect an expensive plug into an expensive radio. <p> If you're into machining you'll know about swarf. If not, think metallic dust. Of course it doesn't have to be metallic, it could be a single grain of sand, or it could be a slightly damaged thread. <p> A couple of months ago I went on the hunt for a tap and die set that would solve this issue once and for all. If you're not familiar with the terms, a tap is like a long bolt with a square head and a die is like a thick washer with holes cut out. <p> In addition to being hardened, they each have cutting edges, which allows these two tools to do their job, the job of cutting threads. <p> Normally you'd use a tap to make a thread into a hole that you've drilled. You'd use a die to make a thread onto a rod that you have. There's lots of technique associated with this, cutting fluids, alignment, pressure and the like. Plenty of relaxing YouTube videos around - which is how I came upon this idea in the first place. <p> You can also use a tap or a die to cut across an existing thread and you can do this with connectors. <p> A die, threaded over a socket, will clean up the socket threads. Similarly a tap screwed into a plug will clean up the plug thread. There's a disclaimer coming for that last point, but stick around. <p> Trying to find a tap and die to match can be a challenge. The PL259, SO239 and N-type connectors are all 5/8th size threads. They're 24 turns per inch, and also known as UNEF (Uniform November Echo Foxtrot) threads, or Unified Extra Fine. <p> So if you start on your hunt, you'll be looking for 5/8th, 24 TPI, UNEF taps and dies. <p> I found mine online at $15 or so from a US supplier. Got to me in about a week. <p> When the